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Yuan, Yi, Jun Ding, Chao Huang, Xia Ma, Xun Qu i Chenjiang Guo. "Broadband Linear to Circular Polarizer Based on Multilayer Frequency-Selective Surface". International Journal of Antennas and Propagation 2023 (21.03.2023): 1–7. http://dx.doi.org/10.1155/2023/8624191.
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In this work, a transmission polarizer is described by using a frequency-selective surface to transform linearly polarized waves into circularly polarized waves. The linear to circular (LTC) polarizer consists of four layers. Two types of unit cells are designed in the LTC polarizer to improve design freedom. As a result, two orthogonal polarized components of transmission waves display nearly 90° phase differences while maintaining nearly high transparency for the generation of CPWs. The less than 3 dB axial ratio with a fractional width of over 76.8% from 9.20 to 20.67 GHz for this LTC polarizer is obtained. Even when the incident angle reaches 20°, its operating frequency band covers 9.69 to 20.21 GHz. Compared with the converters proposed before, the one proposed in this paper has a wider bandwidth. In order to evaluate the design strategy, a prototype is manufactured and tested. The results of the simulation and the experiment are in good accord.
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Mangi, Farman Ali, Shaoqiu Xiao, Ghulam Ali Mallah, Deedar Ali Jamro, Imran Memon i Ghulam Fatima Kakepoto. "Multiband Circular Polarizer Based on Fission Transmission of Linearly Polarized Wave forX-Band Applications". Journal of Electrical and Computer Engineering 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/4293089.
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A multiband circular polarizer based on fission transmission of linearly polarized wave forx-band application is proposed, which is constructed of 2 × 2 metallic strips array. The linear-to-circular polarization conversion is obtained by decomposing the linearly incidentx-polarized wave into two orthogonal vector components of equal amplitude and 90° phase difference between them. The innovative approach of “fission transmission of linear-to-circular polarized wave” is firstly introduced to obtain giant circular dichroism based on decomposition of orthogonal vector components through the structure. It means that the incident linearly polarized wave is converted into two orthogonal components through lower printed metallic strips layer and two transmitted waves impinge on the upper printed strips layer to convert into four orthogonal vector components at the end of structure. This projection and transmission sequence of orthogonal components sustain the chain transmission of electromagnetic wave and can achieve giant circular dichroism. Theoretical analysis and microwave experiments are presented to validate the performance of the structure. The measured results are in good agreement with simulation results. In addition, the proposed circular polarizer exhibits the optimal performance with respect to the normal incidence. The right handed circularly polarized wave is emitted ranging from 10.08 GHz to 10.53 GHz and 10.78 GHz to 11.12 GHz, while the left handed circular polarized wave is excited at 10.54 GHz–10.70 GHz and 11.13 GHz–11.14 GHz, respectively.
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Guo, Zhengfeng, Honggang Gu, Yali Yu, Zhongming Wei i Shiyuan Liu. "Broadband and Incident-Angle-Modulation Near-Infrared Polarizers Based on Optically Anisotropic SnSe". Nanomaterials 13, nr 1 (27.12.2022): 134. http://dx.doi.org/10.3390/nano13010134.
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Optical anisotropy offers an extra degree of freedom to dynamically and reversibly regulate polarizing optical components, such as polarizers, without extra energy consumption and with high modulating efficiency. In this paper, we theoretically and numerically design broadband and incident-angle-modulation near-infrared polarizers, based on the SnSe, whose optical anisotropy is quantitatively evaluated by the complete dielectric tensor, complex refractive index tensor, and derived birefringence (~|Δn|max = 0.4) and dichroism (~|Δk|max = 0.4). The bandwidth of a broadband polarizer is 324 nm, from 1262 nm to 1586 nm, with an average extinction ratio above 23 dB. For the incident-angle-modulation near-infrared polarizer, the high incident angles dynamically and reversibly modulate its working wavelength with a maximum extinction ratio of 71 dB. Numerical simulations and theoretical calculations reveal that the considerable absorption for p light and continuously and relatively low absorption of s light lead to the broadband polarizer, while the incident-angle-modulation one mainly arises from the blue shift of corresponding wavelength of p light’s minimum reflectance. The proposed novel design of polarizers based on SnSe are likely to be mass-produced and integrated into an on-chip system, which opens up a new thought to design polarizing optical components by utilizing other low-symmetry materials.
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Jiang, Yannan, Jing Zhao i Jiao Wang. "Reconfigurable Polarizer Based on Bulk Dirac Semimetal Metasurface". Crystals 10, nr 3 (21.03.2020): 228. http://dx.doi.org/10.3390/cryst10030228.
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In this paper, we propose a reflective polarizer in terahertz regime, which utilizes the Bulk-Dirac-Semimetal (BDS) metasurface can be dynamically tuned in broadband. The proposed polarizer is capable of converting the linear polarized wave into the circular polarized or the cross polarized waves by adjusting the Fermi energy (EF) of the BDS. In the frequency range of 0.51 THz and 1.06 THz, the incident linear polarized wave is converted into a circular polarized wave with an axial ratio (AR) less than 3 dB when EF = 30 meV. When EF = 45 meV, the cross-polarization conversion is achieved with the polarization conversion ratio (PCR) greater than 90% in the band of 0.57−1.12 THz. Meanwhile, the conversion efficiencies for both polarization conversions are in excess of 90%. Finally, the physical mechanism is revealed by the decomposition of two orthogonal components and the verification is presented by the interference theory.
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Ji, Ruonan, Chuan Jin, Kun Song, Shao-Wei Wang i Xiaopeng Zhao. "Design of Multifunctional Janus Metasurface Based on Subwavelength Grating". Nanomaterials 11, nr 4 (19.04.2021): 1034. http://dx.doi.org/10.3390/nano11041034.
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In this paper, a Janus metasurface is designed by breaking the structural symmetry based on the polarization selection property of subwavelength grating. The structure comprises three layers: a top layer having a metallic nanostructure, a dielectric spacer, and a bottom layer having subwavelength grating. For a forward incidence, the metal-insulator-metal (MIM) structure operates as a gap plasmonic cavity if the linearly polarized (LP) component is parallel to the grating wires. It also acts as a high-efficiency dual-layer grating polarizer for the orthogonal LP component. For the backward incidence, the high reflectance of the grating blocks the function of the gap plasmonic cavity, leading to its pure functioning as a polarizer. A bifunctional Janus metasurface for 45 degrees beam deflector and polarizer, with a transmission of 0.87 and extinction ratio of 3840, is designed at 1.55 μm and is investigated to prove the validity of the proposed strategy. Moreover, the proposed metasurface can be cascaded to achieve more flexible functions since these functions are independent in terms of operational mechanism and structural parameters. A trifunctional Janus metasurface that acts as a focusing lens, as a reflector, and as a polarizer is designed based on this strategy. The proposed metasurface and the design strategy provide convenience and flexibility in the design of multifunctional, miniaturized, and integrated optical components for polarization-related analysis and for detection systems.
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Li, Songquan, Laixu Gao, Changwei Zou, Wei Xie, Yong Wei, Canxin Tian, Zesong Wang, Feng Liang, Yanxiong Xiang i Qian Yang. "A Polarization-Independent Fiber-Optic SPR Sensor". Sensors 18, nr 10 (22.09.2018): 3204. http://dx.doi.org/10.3390/s18103204.
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Fiber-optic surface plasmon resonance (SPR) sensors possess the advantages of small size, flexible, allowing for a smaller sample volume, easy to be integrated, and high sensitivity. They have been intensively developed in recent decades. However, the polarizing nature of the surface plasmon waves (SPWs) always hinders the acquisition of SPR spectrum with high signal-noise ratio in wavelength modulation unless a polarizer is employed. The addition of polarizer complicates the system and reduces the degree of compactness. In this work, we propose and demonstrate a novel, polarization-independent fiber-optic SPR sensor based on a BK7 bi-prism with two incident planes orthogonal to each other. In the bi-prism, TM-polarized components of non-polarized incident lights excite SPWs on the first sensing channel, meanwhile the TE components and the remaining TM components are reflected, then the reflected TE components serve as TM components of incident lights for the second sensing channel to excite SPWs. Simulations show the proposed SPR structure permit us to completely eliminate the polarization dependence of the plasmon excitation. Experimental results agree well with the simulations. This kind of devices can be considered an excellent option for development of simple and compact SPR chemical sensors.
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Piltyay, S., A. Bulashenko, V. Shuliak i O. Bulashenko. "Electromagnetic Simulation of New Tunable Guide Polarizers with Diaphragms and Pins". Advanced Electromagnetics 10, nr 3 (26.10.2021): 24–30. http://dx.doi.org/10.7716/aem.v10i3.1737.
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In this article we present the results of mathematical simulation, development and optimization of a waveguide polarizer with a diaphragm and pins. A mathematical model was developed using the proposed approach on the example of a waveguide polarizer with one diaphragm and two pins. The diaphragm and pins were modeled as inductive or capacitive elements for two types of linear polarization of the fundamental modes. The applied model uses a wave scattering matrix. The total matrix of a polarizer was obtained using wave matrices of transmission of individual elements of the device structure. Using the elements of the common S-parameters the electromagnetic characteristics of the device, which is considered, were obtained. To check the performance of the developed mathematical model, it was simulated in a software using the finite element technique in the frequency domain. The designed structure of the polarizer is adjustable due to mechanical change in the length of the pins. The developed waveguide polarizer with one diaphragm and two pins provides a reflection coefficient of less than 0.36 and a transmission coefficient of more than 0.93 for two types of polarizations. Therefore, a new theoretical method was developed in the article for analysis of scattering matrix elements of a waveguide polarizer with diaphragms and pins. It can also be used for the development of new tunable waveguide polarizers, filters and other components with diaphragms and pins.
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Polavarapu, Prasad L., i Zhengyu Deng. "Differential Polarized Reflectance Spectroscopy at Air/Water and Air/Metal Interfaces". Applied Spectroscopy 50, nr 1 (styczeń 1996): 91–97. http://dx.doi.org/10.1366/0003702963906807.
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We report the direct measurement of differential polarized reflectance spectra for samples at air/water and air/metal interfaces. The central component for these measurements is a polarization-division interferometer (PDI). This interferometer uses an in-house-designed beamsplitter constructed in-house from a BaF2 polarizer and a matching substrate. In conjunction with a linear polarizer in front of the source and two rooftop mirrors, one in each arm of the interferometer, the PDI divides the input beam into two orthogonal linear polarization components, recombines them for interference at the beamsplitter, and directs the output beam at 90° to the direction of the input beam. Collimated light rays exiting the interferometer are focused by an f/5 lens and bent from the horizontal propagating axis by a ZnSe wedge to give an angle of incidence of ∼75°, at the sample. The reflected rays are brought back to the horizontal propagation direction by another ZnSe wedge and focused onto the detector by an f/1 lens. The interferogram obtained in this manner represents the differential polarized reflectance interferogram whose cosine Fourier transform directly gives the differential polarized reflectance spectrum. Thus, these spectra were obtained without need for the commonly used photoelastic modulator. Representative spectra for monolayers on a water surface and for samples on a gold surface are presented.
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Guo, Jiacong, Rentang Zhao, Ji Li, Min Zhang i Zhongjing Xie. "P‐12.6: The application study of coated polarizer for TFT‐LCD panels". SID Symposium Digest of Technical Papers 54, S1 (kwiecień 2023): 874–75. http://dx.doi.org/10.1002/sdtp.16442.
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For TFT‐LCD industries, polarizer films are essential components, which directly determine the image quality of panels. The market proposes new trends of thin thickness and large size for TFT‐LCD panels, including applying polarizer films. The technology of coating linear polarizer could readily realize these demands and own the potential of being directly fabricated on glass substrates. Herein, we study the preparation process of coating a polarizer on a PET substrate and aim to enhance the optical performance. The coated polarizer with the polarization degree of 99.9% was successfully fabricated and applied at the 32‐inch TFT‐LCD panels with the contrast ratio of 1200. This technology exhibits a great application potential for next‐generation polarizer films be integrated on liquid crystal cell.
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Michalik, Damian Arkadiusz, Paweł S. Jung, Bartłomiej W. Klus, Andrzej Kowalik, Anna Rojek, Urszula A. Laudyn i Mirosław A. Karpierz. "Chromium plasmonic polarizer for high intensity light". Photonics Letters of Poland 9, nr 3 (30.09.2017): 76. http://dx.doi.org/10.4302/plp.v9i3.767.
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In this work, we investigate a thin-film polarizer for a high intensity of the electromagnetic (EM) beam based on Cr nano wire arrays. Commonly used thin-film polarizing components are very sensitive for high power of EM waves and can be easily damaged by focused beams. The solution to this problem could be the thin-film polarizer based on metallic subwavelengths structures. This type of optical element has huge resistance comparing to typical thin-film polarizers. However, designing such an optical element for proper wavelength of EM wave and transmissions is not easy task. In this paper we present numerical as well as experimental results for specially designed chromium thin-film polarizer for wavelength 532nm Full Text: PDF ReferencesW. Zhou, K. Li, C. Song, P. Hao, M. Chi, M. Yu and Y. Wu, "Polarization-independent and omnidirectional nearly perfect absorber with ultra-thin 2D subwavelength metal grating in the visible region", Opt. Express 23, 11 (2015). CrossRef W. L. Barnes, A . Dereux, and T. W. Ebbesen, "Surface plasmon subwavelength optics", Nature 424, 824-830 (2003). CrossRef C. Lee, E. Sim, D. Kim, "Blazed wire-grid polarizer for plasmon-enhanced polarization extinction: design and analysis", Opt. Express 25, 7 (2017). CrossRef A. Lehmuskero, Metallic thin film structures and polarization shaping gratings (University of Eastern Finland 2010).Y. Leroux, J. C. Lacroix, C. Fave, V. Stockhausen, N. Felidj, J. Grandm, A. Hohenau, J. R. Krenn, "Active plasmonic devices with anisotropic optical response: a step toward active polarizer", Nano Lett. 5, 9 (2009). CrossRef R. T. Perkins, D. P. Hansen, E. W. Gardner, J. M. Thorne, A. A. Robbins, Broadband wire grid polarizer for the visible spectrum, US 6122103 (2000). DirectLink D. M. Sullivan, Electromagnetic simulation using the FDTD method, New York: IEEE Press Series (2000). CrossRef J. P. Berenger, Perfectly Matched Layer (PML) for Computational Electromagnetics, Morgan & Claypool Publishers (2007). CrossRef Yu, W., and R. Mittra, "A conformal FDTD software package modeling antennas and microstrip circuit components", IEEE Antennas Propagat. Magazine 42, 28 (2000) . CrossRef L. W. Bos, D. W. Lynch, "Optical Properties of Antiferromagnetic Chromium and Dilute Cr-Mn and Cr-Re Alloys", Phys. Rev. Sect. B, 2, 4267 (1970). CrossRef
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Bolduc, Martin, Michel Poirier, Gregory Chauve, Hassane Oulachgar, Tom Tiwald, Pierre Laperle, David Gay i in. "Surface Modification of Nanocrystalline Cellulose toward a Tunable Optical Polarizer". MRS Advances 1, nr 10 (28.12.2015): 651–57. http://dx.doi.org/10.1557/adv.2015.45.
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ABSTRACTNanocrystalline cellulose (NCC) solid films obtained from evaporated aqueous heterogeneous mixtures retain the self-assembled chiral nematic order formed in the suspension. These semi-translucent films are iridescent and reflect or transmit circularly polarized visible light (400-700nm) due to the chiral properties of the self-assembled nanostructure. This effect occurs at different wavelengths depending on the pitch of the helical structure. In this paper, NCC films have been fabricated from different recipes to produce various helix pitches. The corresponding red-shift in the optical wavelength has been obtained by means of Spectrophotometry measurements. Preliminary experiments have been performed to investigate optical polarization effects as function of angles of incidence using ellipsometry. Finally, laser micromachining results on NCC films may suggest feasibility for integration as tunable light polarizer components.
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El-Agez, Taher M., i Sofyan A. Taya. "A Fourier Ellipsometer Using Rotating Polarizer and Analyzer at a Speed Ratio 1 : 1". Journal of Sensors 2010 (2010): 1–7. http://dx.doi.org/10.1155/2010/706829.
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We propose theoretically a spectroscopic ellipsometer in which the polarizer and the analyzer are rotating synchronously in the same direction with the same angular speed. The light intensity received by the detector contains four components, one dc and three AC terms, with frequencies of , , and . The main advantage of the proposed ellipsometer is that one can extract the ellipsometric parameters and from the AC Fourier coefficients without relying on the dc component which is considered to be a serious problem in rotating-analyzer or -polarizer ellipsometers. This allows measurements in a semidark room without worrying about stray light problems, dark currents in detectors, and long-term fluctuations in light sources. The results from the simulated spectra of the complex refractive index of c-Si and Au are presented. The noise effect on the proposed ellipsometer was simulated and plotted for the two samples.
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Kato, Hiroki, Norio Koma, Junji Toda, Noriaki Mochizuki, Takahiro Higeta i Takuto Nishiguchi. "56-2: Development of a Higher-Performance Polarizer with Dye Components". SID Symposium Digest of Technical Papers 47, nr 1 (maj 2016): 757–60. http://dx.doi.org/10.1002/sdtp.10758.
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Okazaki, Yutaka, Misaki Kimura i Takashi Sagawa. "(Invited) One-Dimensionally Aligned Quantum Rods for Generation of Highly-Pure Circularly Polarized Light with High Light Intensity". ECS Meeting Abstracts MA2022-01, nr 13 (7.07.2022): 926. http://dx.doi.org/10.1149/ma2022-0113926mtgabs.
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Converting non-polarized visible light (natural light) into circular polarized (CP) light is currently an important issue because of the attractive properties of CP light such as acceleration of photosynthesis and enhancement of conversion efficiency of photovoltaics[1,2]. Until now, various methods for creating CP visible light, such as filtration by circular polarizer, selective reflection by chiral liquid crystal structures, and circular polarized luminescence (CPL) from chiral luminophores[3], have been reported. However, creation of highly-pure CP visible light with high light intensity is still considered as challenging issue. In this presentation, we propose an approach for creating highly-pure CP visible light with high light intensity by converting linearly polarized luminescence (LPL) using quarter-wave plate. In this work, we put spotlight on colloidal semiconductor quantum rods (QRs) because of its unique advantages described as follows: (1) Absorption coefficient and emission quantum yield are relatively high. (2) Sharp emission peaks are expected. (3) Variety of QRs with different emission colors can be excited by irradiation of single-wavelength light. We selected CdSe/CdS core/shell QRs as LPL generating 1D nanostructure. CdSe/CdS core/shell QRs were synthesized by hot-injection method. As shown in Figure 1a, the obtained suspension showed orange-colored strong emission under UV light irradiation. TEM image of the dried sample of the QRs toluene suspension indicates that the average length, average width of the obtained rod-like nanostructures were about 30 nm and 4.5 nm, respectively. After QRs/toluene suspension was mixed with poly(ethylene-co-vinyl acetate) (EVA)/toluene solution, the mixture was casted on glass slide and dried it under air. Then, the prepared composite polymer film was stretched in one direction and was attached on glass slide. When the luminescence from the QRs/EVA stretched film was observed under the linear polarizer placed in parallel direction to the stretching direction, the observed light was brighter than that of perpendicular direction (Figure 1c). By measuring the photoluminescence of parallel (I//) and perpendicular (I⊥) components under depolarized excitation at 450 nm, the QRs/EVA stretched film showed clear LPL property with constant ratio (CR) = 5.4, defined as CR = I// / I⊥ (Figure 1b). Furthermore, when the QRs/EVA stretched film was combined with a quarter-wave plate placed at 45° to the stretching direction and was observed through the right-handed (RH) or left-handed (LH) circular polarizer, brighter light was observed through LH circular polarizer (Figure 1d). By quantitative evaluation of RH- and LH-CP light components, total emission includes 82% of LH-CP light and 18% of RH-CP light (Figure 1e). These results indicate that the combination of the QRs/EVA stretched film and quarter-wave plate generate highly-pure CP light which can be distinguished by the naked eye (Figure 2d). Interestingly, the handedness of CP light can be switched by simply changing the angle between fast axis of the quarter-wave plate and stretching direction of LPL films (Figure 1f). In this presentation, we will also discuss about multiplexing of optical information by using CP light conversion. [1] W. Qin et. al., J. Phys. Chem., 2018, 122, 12566-12571. [2] B. Hu et. al., ACS Photonics, 2017, 4, 2821-2827. [3] P. Duan, M. Liu et. al., Adv. Mater. 2020, 32, 1900110. Figure 1
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Polavarapu, Prasad L., Zhengyu Deng i Gang-Chi Chen. "Polarization-Division Interferometry: Time-Resolved Infrared Vibrational Dichroism Spectroscopy". Applied Spectroscopy 49, nr 2 (luty 1995): 229–36. http://dx.doi.org/10.1366/0003702953963797.
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We report the first direct measurements of time-resolved Fourier transform infrared vibrational dichroism (TR/FT-IR/VD). The central component for these measurements is a polarization-division interferometer (PDI). This interferometer uses an in-house-designed beamsplitter constructed in-house from a BaF2 polarizer and a matching substrate. In conjunction with a linear polarizer in front of the source and two rooftop mirrors, one in each arm of the interferometer, the PDI divides the input beam into two orthogonal linear polarization components, recombines them for interference at the beamsplitter, and directs the output beam at 90° to the direction of input beam. The signals measured as a function of the moving mirror position in the PDI represent the linear/circular dichroism interferograms, whose cosine/sine Fourier transforms yield linear/circular dichroism spectra. Time-resolved dichroism interferograms were measured with the use of this PDI with the asynchronous external perturbation method. Microsecond time-resolved linear dichroism spectra of a nematic liquid crystal, under the influence of bipolar electric field oscillating at 2 kHz, were measured and presented as the first examples.
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Polavarapu, Prasad L., Gang-Chi Chen i Stephen Weibel. "Development, Justification, and Applications of a Mid-Infrared Polarization-Division Interferometer". Applied Spectroscopy 48, nr 10 (październik 1994): 1224–35. http://dx.doi.org/10.1366/0003702944027381.
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We report the development of a polarization-division interferometer (PDI) for the mid-infrared region. This interferometer uses a self-designed beamsplitter constructed in-house from a BaF2 polarizer and a matching substrate. In conjunction with a linear polarizer in front of the source and two roof-top mirrors, one in each arm of the interferometer, the PDI divides the input beam into two orthogonal linear polarization components, recombines them for interference at the beamsplitter, and directs the output beam at 90° to the direction of the input beam. Light exiting the interferometer is manipulated entirely with lenses, to avoid polarization distortions that are inherent to the reflecting surfaces of the mirrors. Details of the instrumental design for this mid-infrared PDI are presented. The performance of the PDI is evaluated by measuring the circular dichroism of α-pinene and camphor and the linear dichroism of oriented polypropylene and polystyrene. These measurements establish the utility of the PDI to measure transmission, circular dichroism, and linear dichroism spectra simultaneously without need for any additional components. The dichroic multiplex advantage (ability to measure dichroism in the entire mid-infrared region from a single measurement) and throughput advantage are demonstrated.
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Peverini, O. A., M. Lumia, Z. Farooqui, G. Addamo, G. Virone, F. Paonessa, L. Ciorba i in. "Q-band polarizers for the LSPE-Strip correlation radiometric instrument". Journal of Instrumentation 17, nr 06 (1.06.2022): P06042. http://dx.doi.org/10.1088/1748-0221/17/06/p06042.
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Abstract This paper reports the design, manufacturing and testing of the cluster of polarizers developed for the LSPE-Strip correlation receiver array working in the Q band (39–48 GHz). Since the LSPE experiment targets the measurement of the very faint B-mode component of the Cosmic Microwave Background, the electromagnetic design of the polarizers was conceived in view of minimizing the measurement uncertainties introduced by the polarizers in the LSPE-Strip dual-circular-polarization correlation receiving chain. To this end, the main figures-of-merit of the LSPE-Strip polarizers were derived in terms of the Mueller sub-matrices relating the relevant input and output Stokes parameters. As a result, a dual-ridge layout, in which stepped-ridge discontinuities are interleaved with grooved cavities, was selected. The heights of both the stepped discontinuities and the grooved cavities were considered as design degrees of freedom in order to minimize the differential phase-error between the two principal polarizations of the polarizer w.r.t. the ideal 90-deg value. The latter condition is the one required for converting the incoming circular polarizations into two linearly polarized ones. The polarizer design allows for a complete manufacturing route (mechanical layout, machining process and assembling) exhibiting high accuracy (< 10 μm) for all the units. As a consequence, the measured performance of the whole polarizer cluster is in tight agreement with predictions. Notably, the in-band mean value of the spurious conversion from the total intensity I to the two linearly polarized Stokes parameters Q and U introduced by the polarizers is smaller than -28 dB (mean value of fifty-one polarizers) with a standard deviation less than 1 dB.
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Khurgin, J. B., Y. Sebbag, E. Edrei, R. Zektzer, K. Shastri, U. Levy i F. Monticone. "Emulating exceptional-point encirclements using imperfect (leaky) photonic components: asymmetric mode-switching and omni-polarizer action". Optica 8, nr 4 (16.04.2021): 563. http://dx.doi.org/10.1364/optica.412981.
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Chen, Bingquan, Peng Shi, Yanhua Wang, Yongze Xu, Hongyang Ma, Ruirong Wang, Chunhong Zheng i Pengcheng Chu. "Determining Surface Shape of Translucent Objects with the Combination of Laser-Beam-Based Structured Light and Polarization Technique". Sensors 21, nr 19 (1.10.2021): 6587. http://dx.doi.org/10.3390/s21196587.
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In this study, we focus on the 3D surface measurement and reconstruction of translucent objects. The proposed approach of surface-shape determination of translucent objects is based on the combination of the projected laser-beam-based sinusoidal structured light and the polarization technique. The theoretical analyses are rigorously completed in this work, including the formation, propagation, and physical features of the generated sinusoidal signal by the designed optical system, the reflection and transmission of the projected monochromatic fringe pattern on the surface of the translucent object, and the formation and the separation of the direct-reflection and the global components of the surface radiance of the observed object. The results of experimental investigation designed in accordance with our theoretical analyses have confirmed that accurate reconstructions can be obtained using the one-shot measurement based on the proposed approach of this study and Fourier transform profilometry, while the monochromaticity and the linearly-polarized characteristic of the projected sinusoidal signal can be utilized by using a polarizer and an optical filter simultaneously for removing the global component, i.e., the noised signal contributed by multiply-scattered photons and the background illuminance in the frame of our approach. Moreover, this study has also revealed that the developed method is capable of getting accurate measurements and reconstructions of translucent objects when the background illumination exists, which has been considered as a challenging issue for 3D surface measurement and reconstruction of translucent objects.
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López-Morales, Guadalupe, María del Mar Sánchez-López, Ángel Lizana, Ignacio Moreno i Juan Campos. "Mueller Matrix Polarimetric Imaging Analysis of Optical Components for the Generation of Cylindrical Vector Beams". Crystals 10, nr 12 (18.12.2020): 1155. http://dx.doi.org/10.3390/cryst10121155.
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In this work, we performed a Mueller matrix imaging analysis of two commercial optical components usually employed to generate and manipulate vector beams—a radial polarizer and a liquid-crystal q-plate. These two elements generate vector beams by different polarization mechanisms—polarizance and retardance, respectively. The quality of the vector beams relies on the quality of the device that generates them. Therefore, it is of interest to apply the well-established polarimetric imaging techniques to evaluate these optical components by identifying their spatial homogeneity in diattenuation, polarizance, depolarization, and retardance, as well as the spatial variation of the angles of polarizance and retardance vectors. For this purpose, we applied a customized imaging Mueller matrix polarimeter based on liquid-crystal retarders and a polarization camera. Experimental results were compared to the numerical simulations, considering the theoretical Mueller matrix. This kind of polarimetric characterization could be very helpful to the manufacturers and users of these devices.
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Lin, Taiy-In, Alexander Chen, Shou-I. Chen i Jihperng Leu. "Effects of thermomechanical properties of polarizer components on light leakage in thin-film transistor liquid-crystal displays". Japanese Journal of Applied Physics 54, nr 7 (3.06.2015): 076701. http://dx.doi.org/10.7567/jjap.54.076701.
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Melody, Tanner M., Krishna H. Patel, Peter K. Nguyen i Christopher L. Smallwood. "Low-cost quadrature optical interferometer". American Journal of Physics 91, nr 2 (luty 2023): 132–41. http://dx.doi.org/10.1119/5.0110405.
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We report on the construction and characterization of a low-cost Mach–Zehnder optical interferometer in which quadrature signal detection is achieved by means of polarization control. The device incorporates a generic green laser pointer, home-built photodetectors, 3D-printed optical mounts, a circular polarizer extracted from a pair of 3D movie glasses, and a python-enabled microcontroller for analog-to-digital data acquisition. Components fit inside of a [Formula: see text] space and can be assembled on a budget of less than US$500. The device has the potential to make quadrature interferometry accessible and affordable for instructors, students, and enthusiasts alike.
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Liu, Yueda, Yan Li, Quanming Chen, Sida Li i Yikai Su. "Liquid Crystal Based Head-Up Display with Electrically Controlled Contrast Ratio". Crystals 9, nr 6 (18.06.2019): 311. http://dx.doi.org/10.3390/cryst9060311.
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With the growing demand for driving safety and convenience, Head-Up Displays (HUDs) have gained more and more interest in recent years. In this paper, we propose a HUD system with the ability to adjust the relative brightness of ambient light and virtual information light. The key components of the system include a cholesteric liquid crystal (CLC) film, a geometric phase (GP) liquid crystal lens, and a circular polarizer. By controlling the voltage applied to the GP lens, the contrast ratio of the virtual information light to ambient light could be continuously tuned, so that good visibility could always be obtained under different driving conditions.
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Foskett, J. K. "Simultaneous Nomarski and fluorescence imaging during video microscopy of cells". American Journal of Physiology-Cell Physiology 255, nr 4 (1.10.1988): C566—C571. http://dx.doi.org/10.1152/ajpcell.1988.255.4.c566.
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A video microscope designed to allow low light level fluorescence imaging of cells during simultaneous high-resolution differential interference contrast (DIC) imaging, without the fluorescence light losses of 60-90% normally associated with this contrast-enhancement technique, is described. Transmitted light for DIC imaging, filtered at greater than 620 nm, passes through standard DIC optical components, (1/4 lambda-plate, polarizer, and Wollaston prism) before illuminating the cells. Transmitted light and fluorescence emission pass through a second Wollaston prism but not through the analyzer, which is repositioned more distally in the optical path. Prisms designed to reflect light out a side port of the microscope to a video camera have been replaced with a dichroic mirror. This mirror reflects fluorescence emission out the side port to a low light-sensitive video camera. The spectrally distinct transmitted light continues through the dichroic mirror to an overhead camera through a polarizer (analyzer), which completes the DIC optical path. The fluorescence and DIC images can be viewed simultaneously on side-by-side video monitors, examined sequentially by an image-processing computer, or examined simultaneously using a video splitter/inserter. The ability to image cells with high resolution simultaneously with low light level fluorescence imaging should find wide applicability whenever it is necessary or desirable to correlate fluorescence intensity or distribution with specific cell structure or function.
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Hull, Charles L. H., i Richard L. Plambeck. "The 1.3mm Full-Stokes Polarization System at CARMA". Journal of Astronomical Instrumentation 04, nr 01n02 (czerwiec 2015): 1550005. http://dx.doi.org/10.1142/s2251171715500051.
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The CARMA 1.3[Formula: see text]mm polarization system consists of dual-polarization receivers that are sensitive to right- (R) and left-circular (L) polarization, and a spectral-line correlator that measures all four cross polarizations ([Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]) on each of the 105 baselines connecting the 15 telescopes. Each receiver comprises a single feed horn, a waveguide circular polarizer, an orthomode transducer (OMT), two heterodyne mixers, and two low-noise amplifiers (LNAs), all mounted in a cryogenically cooled dewar. Here we review the basics of polarization observations, describe the construction and performance of key receiver components (circular polarizer, OMT, and mixers — but not the correlator), and discuss in detail the calibration of the system, particularly the calibration of the R–L phase offsets and the polarization leakage corrections. The absolute accuracy of polarization position angle measurements was checked by mapping the radial polarization pattern across the disk of Mars. Transferring the Mars calibration to the well-known polarization calibrator 3C286, we find a polarization position angle of [Formula: see text] for 3C286 at 225[Formula: see text]GHz, consistent with other observations at millimeter wavelengths. Finally, we consider what limitations in accuracy are expected due to the signal-to-noise ratio, dynamic range, and primary beam polarization.
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Yavorskiy, Dmitriy, Maria Szoła, Krzysztof Karpierz, Rafał Rudniewski, Rafał Bożek, Grzegorz Karczewski, Tomasz Wojtowicz, Jerzy Wróbel i Jerzy Łusakowski. "Polarization of Magnetoplasmons in Grating Metamaterials Based on CdTe/CdMgTe Quantum Wells". Materials 13, nr 8 (11.04.2020): 1811. http://dx.doi.org/10.3390/ma13081811.
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Grating metamaterials were fabricated with electron beam lithography on CdTe/CdMgTe modulation doped structures with two non-interacting quantum wells. Two types of samples were studied: with etched gratings and with gratings formed by deposition of Au stripes. The polarization properties at THz frequencies of the gratings were determined at room temperature. It was shown that Au gratings formed a linear polarizer, while etched gratings did not polarize THz radiation. Transmission of circularly polarized THz radiation at low temperatures through a sample with no grating showed a strongly circularly polarized cyclotron resonance transition. Transmission of this radiation through a sample with an etched grating showed a magnetoplasmon transition that was almost perfectly linearly polarized. We concluded that magnetoplasmons in metamaterials with etched gratings are linearly polarized excitations, possibly with a small contribution of a circular component. This work opens the possibility of the detailed study of the polarization of magnetoplasmons, which has not been explored in the past.
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Mamas, Dean L. "Bell tests explained by classical optics without quantum entanglement". Physics Essays 34, nr 4 (30.12.2021): 582. http://dx.doi.org/10.4006/0836-1398-34.4.582.
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A polarized photon interacts with a polarizer through the component of the photon’s electric field which is aligned with the polarizer. This component varies as the cosine of the angle through which the polarizer is rotated, explaining the cosine observed in Bell test data. Quantum mechanics is unnecessary and plays no role.
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Polavarapu, Prasad L., i Gang-Chi Chen. "Polarization-Division Interferometry: Far-Infrared Dichroism". Applied Spectroscopy 48, nr 11 (listopad 1994): 1410–18. http://dx.doi.org/10.1366/0003702944028119.
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We report the first far-infrared dichroism measurements using a polarization-division interferometer (PDI) developed in our laboratory. This interferometer uses a free-standing wire-grid beamsplitter made of tungsten wires. In conjunction with a linear polarizer in front of the source and two roof-top mirrors (one in each arm of the interferometer), the PDI divides the input beam into two orthogonal linear polarization components, recombines them for interference at the beamsplitter, and directs the output beam at 90° to the direction of the input beam. Light exiting the interferometer is manipulated with far-infrared lenses, to avoid polarization distortions that are inherent to the reflecting surfaces of the mirrors. The performance of the PDI is evaluated by measuring the linear dichroism of oriented PVF2 [poly(vinylidenefluoride) and circular dichroism of α-pinene, camphor, and 3-methylcyclohexanone. The dichroic multiplex advantage (ability to measure dichroism in the entire far-infrared region from a single measurement) and throughput advantage are demonstrated. These measurements establish the utility of the PDI in measuring transmission and linear dichroism spectra simultaneously without the need for any additional components. Additional developments appear necessary to establish the circular dichroism measurements when the magnitudes are less than one part in one thousand.
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D'Alessandro, G., L. Mele, F. Columbro, G. Amico, E. S. Battistelli, P. de Bernardis, A. Coppolecchia i in. "QUBIC VI: Cryogenic half wave plate rotator, design and performance". Journal of Cosmology and Astroparticle Physics 2022, nr 04 (1.04.2022): 039. http://dx.doi.org/10.1088/1475-7516/2022/04/039.
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Abstract Setting an upper limit or detection of B-mode polarization imprinted by gravitational waves from Inflation is one goal of modern large angular scale cosmic microwave background (CMB) experiments around the world. A great effort is being made in the deployment of many ground-based, balloon-borne and satellite experiments, using different methods to separate this faint polarized component from the incoming radiation. QUBIC exploits one of the most widely-used techniques to extract the input Stokes parameters, consisting in a rotating half-wave plate (HWP) and a linear polarizer to separate and modulate polarization components. QUBIC uses a step-by-step rotating HWP, with 15° steps, combined with a 0.4°s-1 azimuth sky scan speed. The rotation is driven by a stepper motor mounted on the cryostat outer shell to avoid heat load at internal cryogenic stages. The design of this optical element is an engineering challenge due to its large 370 mm diameter and the 8 K operation temperature that are unique features of the QUBIC experiment. We present the design for a modulator mechanism for up to 370 mm, and the first optical tests by using the prototype of QUBIC HWP (180 mm diameter). The tests and results presented in this work show that the QUBIC HWP rotator can achieve a precision of 0.15° in position by using the stepper motor and custom-made optical encoder. The rotation induces <5.0 mW (95% C.L) of power load on the 4 K stage, resulting in no thermal issues on this stage during measurements. We measure a temperature settle-down characteristic time of 28 s after a rotation through a 15° step, compatible with the scanning strategy, and we estimate a maximum temperature gradient within the HWP of ≤ 10 mK. This was calculated by setting up finite element thermal simulations that include the temperature profiles measured during the rotator operations. We report polarization modulation measurements performed at 150 GHz, showing a polarization efficiency >99% (68% C.L.) and a median cross-polarization χPol of 0.12%, with 71% of detectors showing a χPol + 2σ upper limit <1%, measured using selected detectors that had the best signal-to-noise ratio.
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Li, Yading, Karu P. Esselle i Lvqian Zhang. "A Coupled-Field Expansion Method for Single-Layer and Multilayer Planar Periodic Structures". International Journal of Antennas and Propagation 2012 (2012): 1–16. http://dx.doi.org/10.1155/2012/170963.
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A new, rigorous, field-based, seminumerical analysis method is presented to obtain the reflection and transmission coefficients of 2D planar periodic structures with arbitrarily shaped metallization patterns for both normal and oblique incidence conditions. It is useful for the analysis, design, and optimization of many single-layer and multilayer planar structures, such as frequency-selective surfaces (FSSs), artificial magnetic conductor (AMC) surfaces, electromagnetic bandgap (EBG) structures, some metamaterials and high-impedance surfaces. In this coupled-field expansion method (CFEM), thex- andy-components of the vector magnetic potential in each homogeneous region in a unit cell are expanded in terms of Bloch-Floquet modes and the solution to the coupled-field problem is formulated. The unique, analytical formulation presented here leads to a linear system with reasonably simple matrix elements. By cascading the matrices representing each interface, multilayer periodic structures are analyzed in a very flexible way. Being field based, CFEM does not require substrate Green's functions to analyze surfaces printed on dielectric substrates. The method was validated by analyzing one single-layer periodic surface (a printed AMC on a dielectric substrate) and one multilayer periodic surface (a circular polarizer) and comparing CFEM results with HFSS results.
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Gill, Richard D. "Comment on “Bell tests explained by classical optics without quantum entanglement” by Dean L. Mamas [Phys. Essays 34, 340 (2021)]". Physics Essays 36, nr 1 (31.03.2023): 87–89. http://dx.doi.org/10.4006/0836-1398-36.1.87.
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In a paper published in the journal [Phys. Essays 34, 340 (2021)], Mamas writes “A polarized photon interacts with a polarizer through the component of the photon's electric field which is aligned with the polarizer. This component varies as the cosine of the angle through which the polarizer is rotated, explaining the cosine observed in Bell test data. Quantum mechanics is unnecessary and plays no role”. Mamas is right that according to this physical model, one will observe a negative cosine. However, the amplitude of the cosine curve is 50%, not 100%, and it consequently does not violate any Bell-CHSH inequality. Mamas' physical model is a classic local hidden variables model. The result is illustrated with a Monte Carlo simulation.
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Recouvreux, Pierre, Thomas R. Sokolowski, Aristea Grammoustianou, Pieter Rein ten Wolde i Marileen Dogterom. "Chimera proteins with affinity for membranes and microtubule tips polarize in the membrane of fission yeast cells". Proceedings of the National Academy of Sciences 113, nr 7 (1.02.2016): 1811–16. http://dx.doi.org/10.1073/pnas.1419248113.
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Cell polarity refers to a functional spatial organization of proteins that is crucial for the control of essential cellular processes such as growth and division. To establish polarity, cells rely on elaborate regulation networks that control the distribution of proteins at the cell membrane. In fission yeast cells, a microtubule-dependent network has been identified that polarizes the distribution of signaling proteins that restricts growth to cell ends and targets the cytokinetic machinery to the middle of the cell. Although many molecular components have been shown to play a role in this network, it remains unknown which molecular functionalities are minimally required to establish a polarized protein distribution in this system. Here we show that a membrane-binding protein fragment, which distributes homogeneously in wild-type fission yeast cells, can be made to concentrate at cell ends by attaching it to a cytoplasmic microtubule end-binding protein. This concentration results in a polarized pattern of chimera proteins with a spatial extension that is very reminiscent of natural polarity patterns in fission yeast. However, chimera levels fluctuate in response to microtubule dynamics, and disruption of microtubules leads to disappearance of the pattern. Numerical simulations confirm that the combined functionality of membrane anchoring and microtubule tip affinity is in principle sufficient to create polarized patterns. Our chimera protein may thus represent a simple molecular functionality that is able to polarize the membrane, onto which additional layers of molecular complexity may be built to provide the temporal robustness that is typical of natural polarity patterns.
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Du, Lan, Jing Liu, Xia Wang, Wei Qi Jin, Hong Guo i Lu Lu. "Dual-CCD Complete Stokes Simultaneously Imaging Polarimeter and Experimental Data Analysis". Key Engineering Materials 552 (maj 2013): 305–12. http://dx.doi.org/10.4028/www.scientific.net/kem.552.305.
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Polarization imaging technology that is on the basis of the polarization measurement can change the obtained polarization information into two-dimensional image, from which we can acquire polarization characteristics of target scene just like normal gray image so that this technique is widely used in the fields of military investigation, medical testing, space exploration, meteorology and so on. Traditional imaging polarimeter is time sequence polarization imaging, which is to use sequential rotational polarization components (line polarizer or wave plate etc.) and to combine Fourier analysis method to acquire final Stokes components. But because of the sacrificing of temporal resolution, this technique does not meet the needs of the situation of high-speed dynamic changing scene. While current simultaneously polarization imaging technique commonly uses multiple sets of optical systems and at least four CCD cameras, which have the problems of low energy utilization rate and non-matching performance among the optical sets. To solve the aforementioned problems, we design and implement a set of non-mechanical rotating parts, double Wollaston prisms-based high resolution simultaneously imaging polarimeter. This system uses the specific combination of non-polarizing beam splitter, Wollaston prisms and wave plates to divide the incident target space beam into four optical paths of different polarization states which can be taken into two types: two paths in the reflection part and two paths in the transmission part. Finally the imaging lens converge the beam to different regions of two large array CCD to image four images. To achieve the goal of extracting complete Stokes information, we apply the Stokes vector and Mueller matrix analysis. The article presents systems structure, working theory, calibration method, experiment data analysis and system polarization performance, which provides a good reference for the simultaneously high-speed polarization imaging.
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Gatto, Cheryl L., Barbara J. Walker i Stephen Lambert. "Local ERM activation and dynamic growth cones at Schwann cell tips implicated in efficient formation of nodes of Ranvier". Journal of Cell Biology 162, nr 3 (4.08.2003): 489–98. http://dx.doi.org/10.1083/jcb.200303039.
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Nodes of Ranvier are specialized, highly polarized axonal domains crucial to the propagation of saltatory action potentials. In the peripheral nervous system, axo–glial cell contacts have been implicated in Schwann cell (SC) differentiation and formation of the nodes of Ranvier. SC microvilli establish axonal contact at mature nodes, and their components have been observed to localize early to sites of developing nodes. However, a role for these contacts in node formation remains controversial. Using a myelinating explant culture system, we have observed that SCs reorganize and polarize microvillar components, such as the ezrin-binding phosphoprotein 50 kD/regulatory cofactor of the sodium-hydrogen exchanger isoform 3 (NHERF-1), actin, and the activated ezrin, radixin, and moesin family proteins before myelination in response to inductive signals. These components are targeted to the SC distal tips where live cell imaging reveals novel, dynamic growth cone–like behavior. Furthermore, localized activation of the Rho signaling pathway at SC tips gives rise to these microvillar component–enriched “caps” and influences the efficiency of node formation.
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Wan Ahamad, Wan Mohd Azwady, Dzaraini Kamarun, Mohd Kamil Abd Rahman i Mohamad Shukri Kamarudin. "Modular Surface Plasmon Resonance (SPR) Biosensor Based on Wavelength Modulation". Advanced Materials Research 1107 (czerwiec 2015): 699–705. http://dx.doi.org/10.4028/www.scientific.net/amr.1107.699.
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This paper deals with a new invention of modular surface plasmon resonance (SPR) biosensor device based on wavelength modulation wherein the angle of incidence of the light source is fixed and the shift in wavelength at resonance is monitored. This device is capable of detecting biomolecular binding interactions of different species such as protein and viruses based on changes in the refractive index of the dielectric environment. White light source mounted with a polarizer is used to excite plasmons on the sensor surface which is thin gold film of ~21 μm thickness coated on BK-7 glass. A variable angle reflection sampling system (VARSS) device from Ocean Optics was modified to incorporate the transducer components and sampling accessories. SPR was observed at the angle of incidence of the light fixed at 29°. At this point, plasmon evanescent wave coupling occurred with highest loss of light intensity. HR4000-UV-NIR photodetector is used to observe the change in resonance wavelength when the dielectric environment around the surface of the transducer was changed. Two liquid samples; water (n=1.33) and ethylene glycol (n=1.43) was introduced onto the sensor surface to model changes in wavelength resonance with difference in refractive index of dielectric environment. It was observed that the resonance wavelength for water and ethylene glycol are 590.10 nm and 594.23 nm respectively when reference to air (n=1.00) indicating the workability of the device.
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Hsu, Julia W. P., E. B. McDaniel i S. C. McClain. "Development of Polarization Modulation Near-Field Scanning Optical Microscope and its Application to Mapping Defect-Induced Birefringence in SrTiO3 Bicrystals". Microscopy and Microanalysis 4, S2 (lipiec 1998): 314–15. http://dx.doi.org/10.1017/s1431927600021693.
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Photoelastic measurement is a sensitive optical technique to map strain fields in otherwise isotropic materials. To extend this method to the submicron scale, we combine dynamic polarimetry with nearfield scanning optical microscopy (NSOM) and construct a polarization modulation NSOM (PMNSOM). The 670 nm laser light passes first through a linear polarizer (oriented at 90°), and then through a photoelastic modulator (PEM), and finally through a quarter wave plate. The PEM introduces a sinusoidally time varying phase shift δ0sin(2πft) into the +45° polarization component, where the modulation frequency/is the resonant frequency (50 kHz) of the PEM quartz element. The quarter wave plate (oriented at 0°) transforms this elliptically polarized light into linearly polarized light with its orientation varying sinusoidally at the modulation frequency. This polarized light is then coupled into a single-mode optical fiber leading to the NSOM tip.
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Junkes, N., E. Fürst i W. Reich. "Extended Polarized Emission Structures in the Galactic Plane at 11 cm Wavelength". Symposium - International Astronomical Union 140 (1990): 63–64. http://dx.doi.org/10.1017/s0074180900189569.
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Data from the Effelsberg Galactic plane survey at 11 cm wavelength have been used to produce a survey of polarized intensity in the first Galactic quadrant. Besides polarized sources (Supernova remnants and extragalactic objects) extended polarized emission features are visible, which are not connected to distinct radio sources. To decide whether these features reflect characteristics of the local field or the distant spiral structure of the Galaxy we performed an integration of polarized intensities as a function of Galactic longitude. An anticorrelation with the thermal background component suggests a distance of more than 6 kpc for some components of the polarized emission. This enables us to derive an upper limit for the uniform component of the Galactic magnetic field.
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Яковлев, Д. Д., i Д. A. Яковлев. "Картины рассеяния ортогонально поляризованных компонент света для статистически вращательно-инвариантных мозаичных двулучепреломляющих слоев". Журнал технической физики 126, nr 3 (2019): 324. http://dx.doi.org/10.21883/os.2019.03.47374.314-18.
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AbstractUsing the method of two-point generalized Mueller matrices and the phase screen approximation, we have studied the relationship between the shape of the angular spectra of linearly polarized components of light scattered by randomly inhomogeneous layers of a birefringent material and the correlation structural characteristics of the layers. For statistically rotationally invariant layers, the structural conditions for three types of scattering patterns of linearly polarized components have been revealed: (i) patterns invariant with respect to the azimuthal rotation by 180°, (ii) patterns invariant with respect to the azimuthal rotation by 90°, and (iii) patterns possessing a circular symmetry. For mosaic birefringent layers consisting of homogeneous fragments with different azimuthal orientations of their optic axes, a relationship between the correlation structural properties of the layer and the shape of the scattering pattern of polarized components has been determined. In particular, conditions for the observation of crosslike four-lobed scattering patterns in crossed and parallel polarizers have been determined and the structural characteristic that is responsible for the orientation of such a scattering pattern with respect to the direction of polarization of the incident light has been found. The inferences that were derived have been supported by experimental data and results of numerical simulations.
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Kim, Hyuntai. "Numerical Analysis of Protection Method of Metallic Sub-Wavelength Concentric Arrays for Radially Polarized Light Selection and Its Applications". Sensors 21, nr 13 (30.06.2021): 4480. http://dx.doi.org/10.3390/s21134480.
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Radially polarized light has various advantages on sensing, thanks for its symmetric field distribution. To select radial component, metallic sub-wavelength concentric arrays are widely used. To increase the stability of the metallic nanostructure from mechanical or chemical hazards, a method to apply an additional protective layer has been proposed. The structure was numerically calculated, and optimized structure showed ~97.4% of transmittance for radially polarized component with ~20 dB of polarization extinction ratio compared to the azimuthally polarized component. This result is a 22% increase compared to the case without the protective layer. In addition, the utility the protective layer applied to metallic sub-wavelength concentric arrays is also discussed. The structure has been applied to a binary, concentric optical plate, and showed the same function with radially polarized input, but prohibited azimuthally polarized input. The proposed structure is expected to be applied on numerous centrosymmetric flat optical components.
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Islas-Islas, Juan M., Germán Reséndiz-López, José G. Ortega-Mendoza, Luis García-Lechuga, Adolfo Quiroz, David-Ignacio Serrano-García, Benito Canales-Pacheco i Noel-Ivan Toto-Arellano. "Characterizations and Use of Recycled Optical Components for Polarizing Phase-Shifting Interferometry Applications". Photonics 9, nr 3 (23.02.2022): 125. http://dx.doi.org/10.3390/photonics9030125.
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In this research, we report using optical components such as cubic beam splitters, lenses, diffraction gratings, and mirrors from broken, obsolete, or disused electronic devices to implement a simultaneous polarization-based phase-shifting interferometric system. The system is composed of a polarized Mach–Zehnder interferometer (PMZI) which generates a sample pattern coupled to a 4f imaging system with a diffraction grating placed on its Fourier plane. Such a diffractive element replicates the pattern generated by the PMZI, and each replica is centered and modulated by each diffraction order generated by the grating. The corresponding individual phase shifts are controlled by placing linear polarizers with known angles in front of each replica. Experimental results are presented using several phase samples such as an oil drop, a pseudoscorpion claw, a microarthropod, and red blood cells. In addition, a comparison of the retrieved phase was conducted by employing two different phase demodulation algorithms.
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Baram, Yoram. "Learning by Kernel Polarization". Neural Computation 17, nr 6 (1.06.2005): 1264–75. http://dx.doi.org/10.1162/0899766053630341.
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Kernels are key components of pattern recognition mechanisms. We propose a universal kernel optimality criterion, which is independent of the classifier to be used. Defining data polarization as a process by which points of different classes are driven to geometrically opposite locations in a confined domain, we propose selecting the kernel parameter values that polarize the data in the associated feature space. Conversely, the kernel is said to be polarized by the data. Kernel polarization gives rise to an unconstrained optimization problem. We show that complete kernel polarization yields consistent classification by kernel-sum classifiers. Tested on real-life data, polarized kernels demonstrate a clear advantage over the Euclidean distance in proximity classifiers. Embedded in a support vectors classifier, kernel polarization is found to yield about the same performance as exhaustive parameter search.
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Turčanová, Michaela, Martin Hrtoň, Petr Dvořák, Kamil Novák, Markéta Hermanová, Zdeněk Bednařík, Stanislav Polzer i Jiří Burša. "Full-Range Optical Imaging of Planar Collagen Fiber Orientation Using Polarized Light Microscopy". BioMed Research International 2021 (28.11.2021): 1–13. http://dx.doi.org/10.1155/2021/6879765.
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A novel method for semiautomated assessment of directions of collagen fibers in soft tissues using histological image analysis is presented. It is based on multiple rotated images obtained via polarized light microscopy without any additional components, i.e., with just two polarizers being either perpendicular or nonperpendicular (rotated). This arrangement breaks the limitation of 90° periodicity of polarized light intensity and evaluates the in-plane fiber orientation over the whole 180° range accurately and quickly. After having verified the method, we used histological specimens of porcine Achilles tendon and aorta to validate the proposed algorithm and to lower the number of rotated images needed for evaluation. Our algorithm is capable to analyze 5·105 pixels in one micrograph in a few seconds and is thus a powerful and cheap tool promising a broad application in detection of collagen fiber distribution in soft tissues.
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Kotlyar, V. V., A. G. Nalimov, A. A. Kovalev, A. P. Porfirev i S. S. Stafeev. "Transfer of spin angular momentum to a dielectric particle". Computer Optics 44, nr 3 (czerwiec 2020): 333–42. http://dx.doi.org/10.18287/2412-6179-co-686.
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We show here that in the sharp focus of a linearly polarized laser beam the spin vector flux has only transverse components (the effect of photonic wheels or photonic helicopter). For a linearly polarized optical vortex, the orbit-spin conversion leads to the appearance of both longitudinal and transverse components of the spin density vector in the focus. Spin-orbit conversion is experimentally demonstrated for a circularly polarized Gaussian beam when a transverse energy flux (orbital angular momentum) arises in the focus, which is transmitted to a microparticle and makes it rotate. Switching the handedness of circular polarization (from left to right) switches the microparticle rotation direction. It is also shown here that an azimuthally polarized vortex beam with an arbitrary integer topological charge generates in the focus a spin density vector that only has an axial component (pure magnetization), while the transverse spin flux is absent.
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Zhang, Suxin. "Identification of Railway Power Supply Voltage Sag Source Using Optical Fiber Voltage Sensor". Journal of Nanoelectronics and Optoelectronics 17, nr 3 (1.03.2022): 525–35. http://dx.doi.org/10.1166/jno.2022.3214.
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With the construction of the smart grid and the continuous improvement of voltage levels, the traditional voltage sensor can no longer meet the development needs of the modern power system. There is an urgent need for a new high-quality voltage sensor to replace it. Aiming at the problems of complex structure, difficult adjustment, poor temperature stability, large optical power loss and inconvenient voltage introduction of the existing optical fiber voltage sensor, an optical fiber voltage sensor based on full polarization state detection without polarizer and analyzer is proposed. The sensor only contains three main components: Grin Lens, BGO crystal and total reflection mirror. It has few devices, simple structure and easy alignment. Moreover, the polarization state evolution and high voltage on the transmission line of Pockels effect of BGO crystal are analyzed. The voltage sag simulation model of the electrified railway is established. The sample data of different disturbance sources are obtained with the assistance of the designed optical fiber voltage sensor. S-transformation and Radial Basis Function (RBF) neural networks are introduced and combined with the prototype of electrified railway power quality detection and analysis device to identify voltage sag sources. The designed optical fiber voltage sensor is suspended. There is no electrode or grounding on the sensor, which saves expensive insulators and increases the sensor’s measuring range. The sensor has a good linear relationship in the power frequency AC voltage range of 0~10 kV at room temperature. It is proved that the design is effective. The working condition analysis of the actual railway power supply reveals that it can detect the voltage sag amplitude and disturbance time, and identify the type of voltage sag disturbance source.
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Ferraro, Antonio, Dimitrios C. Zografopoulos, Roberto Caputo i Romeo Beccherelli. "Terahertz polarizing component on cyclo-olefin polymer". Photonics Letters of Poland 9, nr 1 (31.03.2017): 2. http://dx.doi.org/10.4302/plp.v9i1.699.
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Wire-grid polarizers constitute a traditional component for the control of polarization in free-space devices that operate in a broad part of the electromagnetic spectrum. Here, we present an aluminium-based THz wire grid polarizer, fabricated on a sub-wavelength thin flexible and conformal foil of Zeonor polymer having a thickness of 40um. The fabricated device,characterized by means of THz time-domain spectroscopy, exhibitsa high extinction ratio between 30 and 45dB in the 0.3-2.1THz range. The insertion losses oscillate between 0 and 1.1dB andthey stemalmost exclusively from moderate Fabry-Perót reflections and it is engineered forvanishing at 2THz for operation with quantum cascade lasers. Full Text: PDF ReferencesI. F. Akyildiz, J. M. Jornet, C. Han, "Terahertz band: Next frontier for wireless communications", Phys. Commun. 12, 16 (2014). CrossRef M.C. Kemp, P.F. Taday, B.E. Cole, J.A. Cluff, A.J. Fitzgerald, W.R. Tribe, "Security applications of terahertz technology", Proc. SPIE 5070, 44 (2003). CrossRef M. Schirmer, M. Fujio, M. Minami, J. Miura, T. Araki, T. Yasui, "Biomedical applications of a real-time terahertz color scanner", Biomed. Opt. Express 1, 354 (2010). CrossRef R.P. Cogdill, R.N. Forcht, Y. Shen, P.F. Taday, J.R. Creekmore, C.A. Anderson, J.K. Drennen, "Comparison of Terahertz Pulse Imaging and Near-Infrared Spectroscopy for Rapid, Non-Destructive Analysis of Tablet Coating Thickness and Uniformity", J. Pharm. Innov. 2, 29 (2007). CrossRef Y.-C. Shen, "Terahertz pulsed spectroscopy and imaging for pharmaceutical applications: A review", Int. J. Pharm. 417, 48(2011). CrossRef A.G. Davies, A.D. Burnett, W. Fan, E.H. Linfield, J.E. Cunningham, "Terahertz spectroscopy of explosives and drugs", Mater. Today 11, 18 (2008). CrossRef J.F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, D. Zimdars, "THz imaging and sensing for security applications?explosives, weapons and drugs", Semicond. Sci. Technol. 20, S266 (2005). CrossRef D. Saeedkia, Handbook of Terahertz Technology for Imaging, Sensing and Communications (Elsevier, 2013).N. Born, M. Reuter, M. Koch, M. Scheller, "High-Q terahertz bandpass filters based on coherently interfering metasurface reflections", Opt. Lett. 38, 908 (2013). CrossRef A. Ferraro, D.C. Zografopoulos, R. Caputo, R. Beccherelli, "Periodical Elements as Low-Cost Building Blocks for Tunable Terahertz Filters", IEEE Photonics Technol. Lett. 28, 2459 (2016). CrossRef A. Ferraro, D.C. Zografopoulos, R. Caputo, R. Beccherelli, "Broad- and Narrow-Line Terahertz Filtering in Frequency-Selective Surfaces Patterned on Thin Low-Loss Polymer Substrates", IEEE J. Sel. Top. Quantum Electron. 23 (2017). CrossRef B. S.-Y. Ung, B. Weng, R. Shepherd, D. Abbott, C. Fumeaux, "Inkjet printed conductive polymer-based beam-splitters for terahertz applications", Opt. Mater. Express 3, 1242 (2013). CrossRef J.-S. Li, D. Xu, J. Yao, "Compact terahertz wave polarizing beam splitter", Appl. Opt. 49, 4494 (2010). CrossRef K. Altmann, M. Reuter, K. Garbat, M. Koch, R. Dabrowski, I. Dierking, "Polymer stabilized liquid crystal phase shifter for terahertz waves", Opt. Express 21, 12395 (2013). CrossRef D.C. Zografopoulos, R. Beccherelli, "Tunable terahertz fishnet metamaterials based on thin nematic liquid crystal layers for fast switching", Sci. Rep. 5, 13137 (2015). CrossRef G. Isić, B. Vasić, D. C. Zografopoulos, R. Beccherelli, R. Gajić, "Electrically Tunable Critically Coupled Terahertz Metamaterial Absorber Based on Nematic Liquid Crystals", Phys. Rev. Appl. 3, 064007 (2015). CrossRef K. Iwaszczuk, A.C. Strikwerda, K. Fan, X. Zhang, R.D. Averitt, P.U. Jepsen, "Flexible metamaterial absorbers for stealth applications at terahertz frequencies", Opt. Express 20, 635 (2012). CrossRef F. Yan, C. Yu, H. Park, E.P.J. Parrott, E. Pickwell-MacPherson, "Advances in Polarizer Technology for Terahertz Frequency Applications", J. Infrared Millim. Terahertz Waves 34, 489 (2013). CrossRef http://www.tydexoptics.com DirectLink K. Imakita, T. Kamada, M. Fujii, K. Aoki, M. Mizuhata, S. Hayashi, "Terahertz wire grid polarizer fabricated by imprinting porous silicon", Opt. Lett. 38, 5067 (2013). CrossRef A. Isozaki, et al., "Double-layer wire grid polarizer for improving extinction ratio", Solid-State Sens. Actuators Microsyst. Transducers Eurosensors XXVII 2013 Transducers Eurosensors XXVII 17th Int. Conf. On, IEEE, pp. 530?533 (2013). DirectLink A. Ferraro, D. C. Zografopoulos, M. Missori, M. Peccianti, R. Caputo, R. Beccherelli, "Flexible terahertz wire grid polarizer with high extinction ratio and low loss", Opt. Lett. 41, 2009(2016). CrossRef M.S. Vitiello, G. Scalari, B. Williams, P.D. Natale, "Quantum cascade lasers: 20 years of challenges", Opt. Express 23, 5167(2015). CrossRef A. Podzorov, G. Gallot, "Low-loss polymers for terahertz applications", Appl. Opt. 47, 3254(2008). CrossRef
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Greiner, Cherry, Stephanie Grainger, Samantha Farrow, Alena Davis, Jimmy L. Su, Matthew D. Saybolt, Robert Wilensky, Sean Madden i Stephen T. Sum. "Robust quantitative assessment of collagen fibers with picrosirius red stain and linearly polarized light as demonstrated on atherosclerotic plaque samples". PLOS ONE 16, nr 3 (18.03.2021): e0248068. http://dx.doi.org/10.1371/journal.pone.0248068.
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Collagen is an important component in maintaining structural integrity and functionality of tissues and is modulated in various biological processes. Its visualization and possible quantification using histopathological stains can be important for understanding disease progression or therapeutic response. Visualization of collagen fiber with the histological stain picrosirius red (PSR) is enhanced with polarized light and quantitative analysis is possible using circular polarizers. However, linear polarizers are more commonly available and easier to optically align. The objective of the present study is to demonstrate a novel image acquisition technique and analysis method using linearly polarized light. The proposed imaging technique is based on image acquisition at multiple slide rotation angles, which are co-registered to form a composite image used for quantitative analysis by pixel intensity or pixel counting. The technique was demonstrated on multiple human coronary samples with varying histopathologies and developed specifically to analyze cap collagen in atherosclerotic plaque. Pixel counting image analysis was found to be reproducible across serial tissue sections and across different users and sufficiently sensitive to detect differences in cap structural integrity that are likely relevant to prediction of rupture risk. The benefit of slide rotation angle under linear polarization to acquire images represents a feasible and practical implementation for expanding the general utility of PSR for quantitative analysis.
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Lucas, Eliana P., Ichha Khanal, Pedro Gaspar, Georgina C. Fletcher, Cedric Polesello, Nicolas Tapon i Barry J. Thompson. "The Hippo pathway polarizes the actin cytoskeleton during collective migration of Drosophila border cells". Journal of Cell Biology 201, nr 6 (3.06.2013): 875–85. http://dx.doi.org/10.1083/jcb.201210073.
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Collective migration of Drosophila border cells depends on a dynamic actin cytoskeleton that is highly polarized such that it concentrates around the outer rim of the migrating cluster of cells. How the actin cytoskeleton becomes polarized in these cells to enable collective movement remains unknown. Here we show that the Hippo signaling pathway links determinants of cell polarity to polarization of the actin cytoskeleton in border cells. Upstream Hippo pathway components localize to contacts between border cells inside the cluster and signal through the Hippo and Warts kinases to polarize actin and promote border cell migration. Phosphorylation of the transcriptional coactivator Yorkie (Yki)/YAP by Warts does not mediate the function of this pathway in promoting border cell migration, but rather provides negative feedback to limit the speed of migration. Instead, Warts phosphorylates and inhibits the actin regulator Ena to activate F-actin Capping protein activity on inner membranes and thereby restricts F-actin polymerization mainly to the outer rim of the migrating cluster.
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Reglero-Real, Natalia, Diego García-Weber i Jaime Millán. "Cellular Barriers after Extravasation: Leukocyte Interactions with Polarized Epithelia in the Inflamed Tissue". Mediators of Inflammation 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/7650260.
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During the inflammatory response, immune cells egress from the circulation and follow a chemotactic and haptotactic gradient within the tissue, interacting with matrix components in the stroma and with parenchymal cells, which guide them towards the sites of inflammation. Polarized epithelial cells compartmentalize tissue cavities and are often exposed to inflammatory challenges such as toxics or infections in non-lymphoid tissues. Apicobasal polarity is critical to the specialized functions of these epithelia. Indeed, a common feature of epithelial dysfunction is the loss of polarity. Here we review evidence showing that apicobasal polarity regulates the inflammatory response: various polarized epithelia asymmetrically secrete chemotactic mediators and polarize adhesion receptors that dictate the route of leukocyte migration within the parenchyma. We also discuss recent findings showing that the loss of apicobasal polarity increases leukocyte adhesion to epithelial cells and the consequences that this could have for the inflammatory response towards damaged, infected or transformed epithelial cells.
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Tsuchikawa, Satoru, Misato Torii i Shigeaki Tsutsumi. "Directional Characteristics of Near Infrared Light Reflected from Wood". Holzforschung 55, nr 5 (19.09.2001): 534–40. http://dx.doi.org/10.1515/hf.2001.086.
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Summary A near infrared auto-goniophotometer was designed to acquire detailed information on optical characteristics of a biological material which had a cellular structure, such as wood. The reflected light, which originated from the irradiation of polarized near infrared light, was separated into an unpolarized and a polarized component by using two polarizing filters. The standardized reflected intensities of each component at various incident angles θ and observation angles η, ρup (θ, η) and ρp (θ, η), were measured. Sitka spruce samples with various thicknesses were used. The measurements showed that the directional characteristics of the unpolarized component were affected significantly by the irradiation conditions and the sample thickness. Particularly, these varied with the wavelength of incident light λ. This shows that the directional characteristics models we proposed previously are reasonable. On the other hand, matrices of the directional characteristics for polarized components typically show an elliptical shape which is strongly affected by incident angle and only slightly by λ. Based on these results, the effects of sample thickness on the spectral directional characteristics were determined.
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Thoma, Henrik, Wolfgang Luberstetter, Jürgen Peters i Vladimir Hutanu. "Polarized neutron diffraction using a novel high-Tcsuperconducting magnet on the single-crystal diffractometer POLI at MLZ". Journal of Applied Crystallography 51, nr 1 (1.02.2018): 17–26. http://dx.doi.org/10.1107/s160057671800078x.
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The polarized single-crystal diffractometer POLI is the first neutron scattering instrument routinely using3He spin filters both to produce and to analyse neutron polarization. The instrument, with a non-magnetic goniometer, was designed to perform two types of polarized neutron diffraction experiment: spherical neutron polarimetry, also known as full three-dimensional polarization analysis in zero magnetic field, and classical polarized neutron diffraction, also called the flipping-ratio (FR) method, in high applied magnetic fields. Reported here is the implementation of the FR setup for short-wavelength neutrons on POLI using a new high-Tcsuperconducting magnet with a maximal field of 2.2 T. The complete setup consists of a3He polarizer, a nutator, a Mezei-type flipper, guide fields and dedicated pole pieces, together with the magnet. Each component, as well as the whole setup, was numerically simulated, optimized, built and finally successfully tested under real experimental conditions on POLI. The measured polarized neutron spin transport efficiency is about 99% at different wavelengths,e.g.as short as 0.7 Å, and up to the maximal available field of the magnet. No further depolarization of the3He cells due to stray fields of the magnet occurs. The additional use of the available3He analyser allows uniaxial polarization analysis experiments in fields up to 1.2 T. The results of the first experiment on the field-dependent distribution of the trigonal antiferromagnetic domains in haematite (α-Fe2O3) are presented and compared with the literature data.