Journal articles: 'Structural parameter of refractive index'

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Prajapati, A. N. "Study of Molecular Interaction in Binary Mixtures (1-Propanol + Acetophenone)." Advanced Materials Research 1141 (August 2016): 125–30. http://dx.doi.org/10.4028/www.scientific.net/amr.1141.125.

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Studies on Physico-chemical properties of binary liquid mixtures provide information on the nature of interactions between the constituent of the binaries. Literature provides extensive data on the static dielectric constant (ε0) and refractive index (n) of liquid compounds, but the combined study of all is quite scarce. In the present work static dielectric constant (ε0) and refractive index (n) have been experimentally determined for binary liquid mixture of 1-Propanol (PrOH) with Acetophenone (ACP) over the entire concentration range of mixture composition (0.0 →1.0) at constant temperature 303 K. Static dielectric constant (ε0) and refractive index (n) for the binary mixture have been measured using high precision LCR meter (0.2 MHz) and Abbe’s refractometer respectively. Excess of static dielectric constant (ε0)E and refractive index (n)E are determined and fitted with Redlich-Kister polynomial equation to derive the binary coefficients and standard deviations. For interaction and structural information various parameters namely, Kirkwood correlation factor (g), Kirkwood effective correlation factor (geff), Kirkwood angular correlation factor (gF) and Bruggeman parameter (fB) are determined for the binary mixtures. Variations of these parameters against the concentration of constituents are discussed in terms of molecular interaction between the constituent species.

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Yu, Jing, Tingting Lang, and Huateng Chen. "All-Metal Terahertz Metamaterial Absorber and Refractive Index Sensing Performance." Photonics 8, no. 5 (May 14, 2021): 164. http://dx.doi.org/10.3390/photonics8050164.

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This paper presents a terahertz (THz) metamaterial absorber made of stainless steel. We found that the absorption rate of electromagnetic waves reached 99.95% at 1.563 THz. Later, we analyzed the effect of structural parameter changes on absorption. Finally, we explored the application of the absorber in refractive index sensing. We numerically demonstrated that when the refractive index (n) is changing from 1 to 1.05, our absorber can yield a sensitivity of 74.18 μm/refractive index unit (RIU), and the quality factor (Q-factor) of this sensor is 36.35. Compared with metal–dielectric–metal sandwiched structure, the absorber designed in this paper is made of stainless steel materials with no sandwiched structure, which greatly simplifies the manufacturing process and reduces costs.

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Ciocirlan, Oana, and Olga Iulian. "Density, viscosity and refractive index of the dimethyl sulfoxide + o-xylene system." Journal of the Serbian Chemical Society 74, no. 3 (2009): 317–29. http://dx.doi.org/10.2298/jsc0903317c.

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This work reports the experimental results of the densities, viscosities and refractive indices between 298.15 and 323.15 K of the dimethyl sulfoxide + o-xylene system over the entire composition range of the mixtures. The excess molar volumes (VE), viscosity deviations (?v), excess Gibbs energy of activation of viscous flow (G*E) and deviations in the refraction (?R) were calculated from the experimental data; all the computed quantities were fitted to the Redlich-Kister equation. The system exhibits moderate negative values for the investigated excess properties. The resulting excess functions were interpreted in structural and interactional terms. From the experimental data, the thermodynamic functions of the activation of viscous flow were estimated. The viscosity data were correlated with several semi-empirical equations. The two-parameter McAllister equation can give very good results.

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Hussein, Ahang M., Elham M. A. Dannoun, Shujahadeen B. Aziz, Mohamad A. Brza, Rebar T. Abdulwahid, Sarkawt A. Hussen, Sarkawt Rostam, Dalia M. T. Mustafa, and Dana S. Muhammad. "Steps Toward the Band Gap Identification in Polystyrene Based Solid Polymer Nanocomposites Integrated with Tin Titanate Nanoparticles." Polymers 12, no. 10 (October 10, 2020): 2320. http://dx.doi.org/10.3390/polym12102320.

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In the current study, the film fabrication of polystyrene (PS) based polymer nanocomposites (NCs) with tuned refractive index and absorption edge was carried out using the solution cast method. X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) light characterization techniques were performed. The structural and optical properties of the prepared films were specified. The hump of PS decreased significantly when SnTiO3 nanoparticles (NPs) were introduced. Sharp and high intense peaks of SnTiO3 NPs at a high filler ratio were observed. The crystalline size was determined for SnTiO3 NPs from the sharp crystalline peaks using Debye-Scherrer’s equation and was found to be 25.179 nm, which is close enough to that described by the supplier. Several optical parameters, such as absorption coefficient (α), refractive index (n), and optical dielectric properties, were investigated. The absorption spectra were tuned with increasing SnTiO3NPs. Upon the addition of the NPs to the PS host polymer, the absorption edge undergoes shifting to lesser photon energy sides. The optical dielectric constant (ε′) was correlated to the refractive index. The study of the optical band gap was conducted in detail using both Tauc’s model and the optical dielectric loss (ε″) parameter. The results showed that the ε″ parameter is noteworthy to be measured in the optical band gap study of materials.

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Liu, Yan Jun, and Tong Dai. "Investigation on Dispersion Property of a Novel Photonic Crystal Fiber with Square Array Air Holes." Advanced Materials Research 571 (September 2012): 278–82. http://dx.doi.org/10.4028/www.scientific.net/amr.571.278.

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The dispersion property of a novel photonic crystal fiber with square array air holes was simulated with the vectorial beam propagation method. The impacts of the pitch and hole diameter on the effective area of fundamental mode and the dispersion parameter were evaluated. The results indicate that the effective refractive index decreases and the dispersion parameter increases with air hole diameter increasing and the pitch decreasing, the structure parameters of inner three rings air hole influences the dispersion characteristics greatly. Thus the dispersion property of the photonic crystal fiber can be tailed by the structural parameters.

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Sakiroglu, S. "Linear and nonlinear optical absorption coefficients and refractive index changes in Morse quantum wells under electric field." International Journal of Modern Physics B 30, no. 30 (November 23, 2016): 1650209. http://dx.doi.org/10.1142/s021797921650209x.

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In this paper, we investigate theoretically the effects of electric field on the linear and nonlinear optical properties of Morse quantum wells considering a two-level system. The effective mass approximation and the envelope function approach are used to calculate the energy levels and wave functions. The analytical expressions of the optical properties are obtained by using the compact density-matrix approach. The linear and third-order nonlinear optical absorption coefficients and the refractive index changes are investigated as a function of the incident photon energy for several configurations of the structural parameter and the applied electric field. Numerical results, presented for a typical GaAs/AlGaAs quantum well, reveal that the electric field has a significant effect on the optical characteristics of these structures and intersubband transitions can be modified by tuning the structural range parameter of the potential.

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Aziz, Shujahadeen B., Elham M. A. Dannoun, Dana A. Tahir, Sarkawt A. Hussen, Rebar T. Abdulwahid, Muaffaq M. Nofal, Ranjdar M. Abdullah, Ahang M. Hussein, and Iver Brevik. "Synthesis of PVA/CeO2 Based Nanocomposites with Tuned Refractive Index and Reduced Absorption Edge: Structural and Optical Studies." Materials 14, no. 6 (March 23, 2021): 1570. http://dx.doi.org/10.3390/ma14061570.

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In the current study, polymer nanocomposites (NCPs) based on poly (vinyl alcohol) (PVA) with altered refractive index and absorption edge were synthesized by means of a solution cast technique. The characterization techniques of UV–Vis spectroscopy and XRD were used to inspect the structural and optical properties of the prepared films. The XRD patterns of the doped samples have shown clear amendments in the structural properties of the PVA host polymer. Various optical parameters were studied to get more insights about the influence of CeO2 on optical properties of PVA. On the insertion of CeO2 nanoparticles (NPs) into the PVA matrix, the absorption edge was found to move to reduced photon energy sides. It was concluded that the CeO2 nanoparticles can be used to tune the refractive index (n) of the host polymer, and it reached up to 1.93 for 7 wt.% of CeO2 content. A detailed study of the bandgap (BG) was conducted using two approaches. The outcomes have confirmed the impact of the nanofiller on the BG reduction of the host polymer. The results of the optical BG study highlighted that it is crucial to address the ε” parameter during the BG analysis, and it is considered as a useful tool to specify the type of electronic transitions. Finally, the dispersion region of n is conferred in terms of the Wemple–DiDomenico single oscillator model.

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ATUCHIN, V. V., V. SH ALIEV, B. M. AYUPOV, and I. V. KOROLKOV. "DECREASED REFRACTIVE INDEX OF NANOCRYSTALLINE ZIRCONIUM OXIDE THIN FILMS." International Journal of Modern Physics B 26, no. 02 (January 20, 2012): 1250012. http://dx.doi.org/10.1142/s0217979211102101.

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Amorphous zirconium oxide (a- ZrO 2) thin films were prepared onto fuzzed quartz substrates by ion beam sputtering deposition (IBSD) method in ( Ar + O 2) gas mixture. Optical parameters of the films were evaluated by laser ellipsometry (λ = 632.8 nm ) and optical transmission measurements. Structural parameters were studied by XRD measurements. Variation of refractive index and film thickness have been defined as a function of time of high-temperature annealing at T = 900° C . Formation of monoclinic zirconium oxide (m- ZrO 2) nanocrystals with diameter of ~60 nm embedded into a- ZrO 2 matrix has been found by XRD analysis after long-time annealing.

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Dhanya, I., and C. S. Menon. "Effect of Thickness on Structural and Optical Properties of Tetra-tert- butyl-2, 3-naphthalocyanine Thin Films." E-Journal of Chemistry 8, no. 4 (2011): 1686–95. http://dx.doi.org/10.1155/2011/752982.

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Amorphous tetra-tert-butyl-2, 3-naphthalocyanine thin films have been deposited using physical vapor deposition technique under a varied thickness by adjusting the coating time. By analyzing the x-ray diffraction, the structure of as deposited films is found to be non-crystalline. Different optical properties of these thin films have been investigated by means of optical absorption and reflection spectra. Various optical constants like band gap energy, Egthe width of band tails of localized states into the gap, EUand steepness parameter, β gets calculated and the variation of different optical parameters like refractive index, extinction coefficient, dielectric constants, optical conductivity and surface and volume energy losses with photon energy are estimated.

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Michihata, Masaki, Deqing Kong, Kiyoshi Takamasu, and Satoru Takahashi. "A Simulation Study of Plasmonic Substrate for In-Process Measurement of Refractive Index in Nano-Stereolithography." International Journal of Automation Technology 11, no. 5 (August 30, 2017): 772–80. http://dx.doi.org/10.20965/ijat.2017.p0772.

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Functional surfaces are in demand for recent value-added products. Stereolithography based on evanescent light has been proposed as a technique to fabricate surface nanostructures, but some fabrication error sources must be addressed. In-process measurement is an essential solution to improve the fabrication performance. For in-process measurement in stereolithography, the refractive index of resin is an inherent parameter for product and condition monitoring. This study proposes the in-process measurement of the refractive index of resin based on surface plasmon resonance (SPR). The optical phase response at SPR is highly sensitive to changes in the refractive index of resin but has a narrow sensing range. Therefore, we propose a substrate with a tunable sensing range using lanthanum-modified lead zirconate titanate (PLZT). The structural design was considered using numerical simulation. The SPR conditions were calculated with regard to thickness combinations of PLZT and metal (Ag) films. Depending on these combinations, a sensing range can be tuned on the order of 10-3to 10-4RIU with a sensitivity of 106rad/RIU. However, to realize these performances, the manufacturing accuracy of Ag thin films must be better than 0.1 nm.

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Mekhnache, Mounira, Hayet Benzarouk, and Abdelaziz Drici. "Structural, linear and non-linear optical properties of Cr-doped ZnO thin film for optoelectronics applications." International Journal of Materials Research 112, no. 2 (February 1, 2021): 150–57. http://dx.doi.org/10.1515/ijmr-2020-7977.

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Abstract In this work, optical properties of undoped zinc oxide (ZnO) and chromium (Cr) doped ZnO prepared at different concentrations of Cr (2, 3, and 5 wt.%) on glass substrates by a spray pyrolysis method are reported. The structural properties investigated by X-ray diffraction revealed the hexagonal wurtzite structure, noting that the crystallite size of the films decreases with increasing Cr content. The optical characterization of the samples was carried out using spectral transmittance. The refractive index, energy gap, and extinction coefficient of pure and Cr-doped ZnO thin films have been calculated. The single oscillator model of Wemple–DiDomenico was used to study the dispersion of the refractive index. The oscillator parameters, the single oscillator energy, the dispersion energy, and the static refractive index were determined. The linear optical susceptibility and non-linear optical susceptibility were also studied and discussed. These promising results achieved by Cr-doping of ZnO exhibited an important behavior for technological applications in electronic, optoelectronic devices and non-linear optical applications.

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Zhang, Ji Yan, Wen Li Liu, Lei Yang, and Ming Liang Gao. "Analysis on Refractive Property of Complex Optometry System." Applied Mechanics and Materials 668-669 (October 2014): 1565–68. http://dx.doi.org/10.4028/www.scientific.net/amm.668-669.1565.

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In optometry, simplified models are usually used to analyze refractive property of optometry system on the assumption that lenses are thin and close enough to each other. However, in fact those lenses do have stated center thickness and lens space between them. The simplified models are not suitable for accurate analysis and system design. In this paper, first, accurate mathematic model for refractive property of single spherical and cylindrical lens is established. Next, accurate model is established for complex optometry system with different kinds of lenses combination. Then, influence factors such as lens structural parameter, lens space and lens position are analyzed for refractive property. Results show that correct lens position is very important for complex optometry system. Parallel light should pass lower power lens first and then higher power lens. When lens power and lens space gets bigger the influence of lens space will be more significant on refractive property. For uncertainty component, uncertainty from front and back surface radii are the biggest, secondary is the refractive index and lens space, and uncertainty from lens thickness is the least.

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Chen, Ying, Xinbei Gao, Pei Luo, Yangmei Xu, Jinggang Cao, and Jinchao Xie. "Sensing mechanism analysis on one-dimensional photonic crystal with air slot-porous silicon-air slot F–P cavity." Modern Physics Letters B 33, no. 13 (May 10, 2019): 1950159. http://dx.doi.org/10.1142/s0217984919501598.

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Based on the evanescent wave resonance, a photonic crystal sensing structure with air slot-porous silicon-air slot Fabry–Perot cavity (F–P cavity) is proposed. Taking the F–P cavity as the sensing unit, when the gas to be detected is filled into the sensing unit, the refractive index of the air slot will be changed and the refractive index of the porous silicon layer will also be varied, both of which will shift the resonant peak and greatly increase the sensitivity of the sensor. By adjusting the structural parameters, the quality factor (Q value) can be optimized. A model for the relationship between the resonant wavelength and the refractive index of the detected organic gas was established, and the refractive index sensing performance was analyzed. The results show that the Q value of the structure can attain to 12312.2 and the sensitivity is about 8661.708 nm/RIU, which can provide effective theoretical reference and technical guidance for organic gas detection with low concentration.

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Wu, Tiesheng, Yumin Liu, Zhongyuan Yu, Han Ye, Changgan Shu, Yiwei Peng, Jie Wang, and Huifang He. "Tuning the Fano resonances in a single defect nanocavity coupled with a plasmonic waveguide for sensing applications." Modern Physics Letters B 29, no. 33 (December 10, 2015): 1550218. http://dx.doi.org/10.1142/s0217984915502188.

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A novel surface plasmon polaritons (SPPs) refractive index sensor based on a single defect nanocavity coupled with a metal–insulator–metal (MIM) waveguide is proposed and numerically simulated by using the finite difference time domain (FDTD) method with perfectly matched layer absorbing boundary condition. It is found that the defect structure can realize two Fano resonances and these two Fano resonances originate from two different mechanisms. The results demonstrate the liner correlation between the resonance wavelengths of the device and the refractive index of the material under sensing. Through the optimization of structural parameters, we achieve a theoretical value of the refractive index sensitivity as high as 1800.4 nmRIU[Formula: see text]. It could be utilized to develop ultra-compact nanodevice for high-resolution biological sensing.

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ARASU, P. ADAL, and R. VICTOR WILLIAMS. "EFFECT OF ANNEALING TEMPERATURE ON STRUCTURAL AND OPTICAL PARAMETERS OF SOL–GEL ROUTED MOLYBDENUM OXIDE THIN FILM." Surface Review and Letters 22, no. 04 (June 15, 2015): 1550054. http://dx.doi.org/10.1142/s0218625x15500547.

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The influence of annealing temperature on structural and optical properties of sol–gel routed spin-coated molybdenum tri oxide ( MoO 3) thin films are studied. The higher annealing temperatures improve the crystalline nature of the film. The X-ray diffraction (XRD) study reveals the formation of α-orthorhombic phase at higher annealing temperature and amorphous nature at lower annealing temperature. The optical bandgap of molybdenum tri oxide ( MoO 3) film is found to be 3.3–3.8 eV, and the refractive index of the film is found to be 2.2–2.9. The dispersion curve of the refractive index shows that an abnormal dispersion in the absorption region and normal dispersion in the transparent region are observed. The optical polarizability, optical conductivity, dielectric constant, volume and surface energy loss parameters are evaluated.

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Feng, Li Ping, Zheng Tang Liu, and Qi Jun Liu. "First-Principles Calculations on Structural, Electronic, and Optical Properties of 2H-CuAlO₂." Advanced Materials Research 197-198 (February 2011): 487–90. http://dx.doi.org/10.4028/www.scientific.net/amr.197-198.487.

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Structural, electronic and optical properties of 2H-CuAlO2 were computed, using the plane-wave ultrasoft pseudopotential technique based on the first-principles density functional theory (DFT). The equilibrium lattice parameters, band structure, densities of states (DOS) and charge densities of 2H-CuAlO2 have been obtained. The equilibrium lattice parameters, band structure and DOS are found to be in good agreement with the available experimental and calculational values. The charge densities and the chemical bonding of 2H-CuAlO2 are analyzed, which show that bonding between Cu and O is mainly covalent due to Cu 3d and O 2p hybridization and that bonding between Al and O is mainly ionic. The complex dielectric function, refractive index and absorption coefficient of 2H-CuAlO2 have been predicted. The calculated static dielectric constant and static refractive index of 2H-CuAlO2 is 7.1 and 2.66, respectively.

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Shafi, H. Z., A. Mahmood, Z. Ali, and M. Mehmood. "Optical and Structural Analysis of GeC Thin Films Deposited by Reactive Pulsed Laser Ablation Technique." Key Engineering Materials 442 (June 2010): 178–86. http://dx.doi.org/10.4028/www.scientific.net/kem.442.178.

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GeC thin films have been prepared by reactive pulsed laser ablation technique. Methane pressure (PCH4) was varied from 0 to 75 milli torrs (mT). Optical analysis of all the samples was performed by spectroscopic ellipsometry (SE). The optical constants i.e. refractive index (n), extinction coefficient (k), absorption coefficient (α) and thickness of deposited film(s) were obtained by modeling and simulations of ellipsometric data. It was found that deposition parameter (change in pressure of methane) has a profound effect on the properties of the deposited films. To support our results of optical analysis, other important diagnostic techniques like atomic force microscopy (AFM), Fourier Transform Infrared Spectroscopy (FTIR) etc. were employed.

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Hu, Yao, Jiahang Lv, and Qun Hao. "Refractive Index Measurement of Glass with Arbitrary Shape Based on Brewster’s Law and a Focusing Probe Beam." Sensors 21, no. 7 (April 1, 2021): 2421. http://dx.doi.org/10.3390/s21072421.

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The refractive index is one of the most important parameters of optical glasses and has a significant effect on optical properties. The measurement of optical glasses, especially for optical elements such as lenses, is urgently needed. However, several presented methods require the immersion of the sample in liquid and provide indirect measurements, while others require structural parameters as priori knowledge, which is complex and time-consuming. In this study, a Brewster-Law-based direct and simple measurement method for the refractive index of glasses with arbitrary shapes is proposed, and a laser beam is focused on the surface of the sample as a probe. The incident angle of the chief ray is close to the Brewster angle. The reflected light is collected by an array detector. The refractive index is calculated from the minimum intensity position obtained with image processing. Additionally, a symmetric measurement scheme is proposed to improve the accuracy. Using these methods, a prism and four spherical lens samples with different refractive indices or radii of curvature are tested and error analyses are carried out. Results indicate that the accuracy can reach 10−4.

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Shaimanov, Alexey, and Alexander Baryshev. "Plasmonic magneto-optical nested 2D nanostructures: tailoring responses through effective refractive index." EPJ Web of Conferences 190 (2018): 03011. http://dx.doi.org/10.1051/epjconf/201819003011.

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Spectra of a nested square two-dimensional lattice of metal nanospheres encased in a magneto-optical host were studied. We show that the magneto-optical response of the nanostructures considerably increases due to the plasmon resonances. Moreover, the optical and magneto-optical responses can be strongly altered with a negligible change in structural parameters.

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Sun, Lin, Haixin Lin, Kevin L. Kohlstedt, George C. Schatz, and Chad A. Mirkin. "Design principles for photonic crystals based on plasmonic nanoparticle superlattices." Proceedings of the National Academy of Sciences 115, no. 28 (June 25, 2018): 7242–47. http://dx.doi.org/10.1073/pnas.1800106115.

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Photonic crystals have been widely studied due to their broad technological applications in lasers, sensors, optical telecommunications, and display devices. Typically, photonic crystals are periodic structures of touching dielectric materials with alternating high and low refractive indices, and to date, the variables of interest have focused primarily on crystal symmetry and the refractive indices of the constituent materials, primarily polymers and semiconductors. In contrast, finite difference time domain (FDTD) simulations suggest that plasmonic nanoparticle superlattices with spacer groups offer an alternative route to photonic crystals due to the controllable spacing of the nanoparticles and the high refractive index of the lattices, even far away from the plasmon frequency where losses are low. Herein, the stopband features of 13 Bravais lattices are characterized and compared, resulting in paradigm-shifting design principles for photonic crystals. Based on these design rules, a simple cubic structure with an ∼130-nm lattice parameter is predicted to have a broad photonic stopband, a property confirmed by synthesizing the structure via DNA programmable assembly and characterizing it by reflectance measurements. We show through simulation that a maximum reflectance of more than 0.99 can be achieved in these plasmonic photonic crystals by optimizing the nanoparticle composition and structural parameters.

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Lan, Guilian, Zhongxie Jin, Jinpeng Nong, Peng Luo, Caicheng Guo, Zhengguo Sang, Lei Dong, and Wei Wei. "Narrowband Perfect Absorber Based on Dielectric-Metal Metasurface for Surface-Enhanced Infrared Sensing." Applied Sciences 10, no. 7 (March 27, 2020): 2295. http://dx.doi.org/10.3390/app10072295.

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We proposed a narrowband perfect absorber that was based on dielectric-metal metasurface for wide-band surface-enhanced infrared sensing. It is found that the narrowband perfect absorber can generate the hybrid guided modes with high quality-factor at infrared frequencies, which make the absorber highly sensitive to the surrounded analyte. Moreover, tuning the incident angle can actively modulate the resonant wavelength of absorber. Such an absorber with excellent features is employed to realize both refractive index sensing and infrared vibrational fingerprint sensing on a single substrate. It is demonstrated that a refractive index sensitivity of 1800 nm/RIU and figure of merit of 62 RIU−1 can be obtained as the refractive index sensor. While, as a surface enhanced infrared absorption spectroscopy substrate, two closed vibrational modes of analyte with nanometer thick layers can be effectively identified and selectively detected with 50-folds enhancement by actively tuning the incident angle without any change in the structural parameters (periodicity, width, height, and refractive index of the grating) of the device after fabricating. Our study offers a promising approach for designing high-performance surface-enhanced infrared optical sensors in the infrared region.

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Güneri, Emine. "The Role of Au Doping on the Structural and Optical Properties of Cu₂O Films." Journal of Nano Research 58 (June 2019): 49–67. http://dx.doi.org/10.4028/www.scientific.net/jnanor.58.49.

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The changes in structural and optical properties of the Cu2O films obtained on the glass with different concentrations of Au by the chemical bath method were studied in this work. Lattice parameter, crystal size, preferential orientation and surface tension of the films were calculated using X-ray diffraction data which showed that all of the films were in polycrystalline form. It was determined that the structural parameters of all films were changed with the doping ratio. The surface morphology of the films was imaged using a field emission scanning electron microscope. The optical properties of the films were discovered using the optic spectrometer. Changes in the optical properties were discovered as a function of Au ratio. It was determined that the energy band gap value (2.12 eV-2.02 eV), the refractive index, the extinction coefficient, the real and dielectric coefficients, the optical conductivity, and the skin depth of films varied with Au doping ratio.

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Arshad Javid, M., Zafar Ullah Khan, Zahid Mehmood, Azeem Nabi, Fayyaz Hussain, M. Imran, Muhammad Nadeem, and Naeem Anjum. "Structural, electronic and optical properties of LiNbO3 using GGA-PBE and TB-mBJ functionals: A DFT study." International Journal of Modern Physics B 32, no. 14 (June 5, 2018): 1850168. http://dx.doi.org/10.1142/s0217979218501680.

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In the present work, first-principles calculations were performed to obtain the structural, electronic and optical properties of lithium niobate crystal using two exchange-correlation functionals (GGA-PBE and TB-mBJ). The calculated structural parameters were very close to the experimental values. TB-mBJ functional was found to be good when compared to LDA and GGA functionals in case of bandgap energy of 3.715 eV of lithium niobate. It was observed that the upper valence and lower conduction bands consist mainly the O-2p and Nb-4[Formula: see text] states, respectively. Furthermore, calculations for real and imaginary parts of frequency-dependent dielectric function [Formula: see text] of lithium niobate crystal were performed using TD-DFT method. The ordinary refractive index n[Formula: see text], extraordinary refractive index n[Formula: see text], its birefringence and absorption peaks in imaginary dielectric function [Formula: see text] were also calculated.

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Kong, Lu, Jiangtao Lv, Qiongchan Gu, Yu Ying, Xiaoxiao Jiang, and Guangyuan Si. "Sensitivity-Enhanced SPR Sensor Based on Graphene and Subwavelength Silver Gratings." Nanomaterials 10, no. 11 (October 26, 2020): 2125. http://dx.doi.org/10.3390/nano10112125.

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A novel surface plasmon resonance (SPR) sensor with graphene and subwavelength gratings is proposed to improve the sensing performance. A series of numerical analyses were performed to investigate the effect of structural parameters on the sensing performance, such as minimum reflectance at resonance (MRR), full width at half maximum (FWHM), and resonance angle. The results indicated that near-zero MRR (2.9 × 10−6) and narrow FWHM (about 3.5 deg) could be obtained by optimizing the geometrical parameters. Moreover, the influence of the number of graphene layers on sensitivity was also studied. The maximum sensitivity of the designed sensor could reach 192 deg/refractive index unit (RIU), which is a great enhancement compared to the silver-only SPR sensor. In addition, ethylene glycol solutions with different refractive indices were detected. The results showed that the sensitivity of the sensor could reach 220.67 deg/RIU, and the proposed sensor had excellent linearity between the resonance angle and refractive index, enabling extensive potential practical sensing applications.

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Hui, Bing, Xiuhua Fu, Des Gibson, David Child, Shigeng Song, Lewis Fleming, Guntis Rutins, Hin Chu, Caspar Clark, and Stuart Reid. "Automated Control of Plasma Ion-Assisted Electron Beam-Deposited TiO2 Optical Thin Films." Coatings 8, no. 8 (August 5, 2018): 272. http://dx.doi.org/10.3390/coatings8080272.

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A hollow cathode plasma source has been operated automatically, demonstrating independent control of plasma ion energy and ion current density for plasma ion-assisted electron beam-deposited titania (TiO2). The lanthanum hexaboride hollow cathode design described in this work utilizes both the interior and exterior cathode surfaces, with the additional electrons generated removing the need for a separate neutralizing source. Automatic feedback control of plasma source cathode-to-anode accelerator voltage (AV—via argon gas flow to the anode and/or cathode plasma source areas) and accelerator current (AC—via an external high-current power supply) provides independent control of the ion energy distribution function and ion current density, respectively. Automated run-to-run reproducibility (over six separate deposition runs) in TiO2 refractive index (550 nm) was demonstrated as 2.416 ± 0.008 (spread quoted as one standard deviation), which is well within the required refractive index control for optical coating applications. Variation in refractive index is achievable through control of AV (ion energy) and/or AC (ion current density), directly influencing deposited TiO2 structural phase. Measured dependencies of TiO2 refractive index and extinction coefficient on AV and AC are described. Optimum plasma source parameters for assisted electron beam deposition of TiO2 optical thin-film applications are highlighted.

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Ghanipour, Mahshad, and Davoud Dorranian. "Effect of Ag-Nanoparticles Doped in Polyvinyl Alcohol on the Structural and Optical Properties of PVA Films." Journal of Nanomaterials 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/897043.

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The effect of silver nanoparticles doped in PVA on the structural and optical properties of composite films is studied experimentally. Samples are PVA films of 0.14 mm thickness doped with different sizes and concentrations of silver nanoparticles. Structural properties are studied using X-ray diffraction and FTIR spectrum. Using the reflectance and transmittance of samples, the effect of doped nanoparticles and their concentration on optical parameters of PVA films include absorption coefficient, optical bandgap energy, complex refractive index, complex dielectric function, complex optical conductivity, and relaxation time is extracted and discussed. The dispersion of the refractive index of films in terms of the single oscillator Wemple-DiDomenico (WD) model is investigated and the dispersion parameters are calculated. Results show that by doping silver nanoparticles in PVA, number of Bragg’s planes in the structure of polymer and its crystallinity are increased noticeably. Ag–O bonds are formed in the films and the bandgap energy of samples is decreased. Calculations based on WD model confirm that by doping nanoparticles, the anion strength of PVA as a dielectric medium is decreased.

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Pujol, M. C., X. Mateos, A. Aznar, X. Solans, S. Suriñach, J. Massons, F. Díaz, and M. Aguiló. "Structural redetermination, thermal expansion and refractive indices of KLu(WO4)2." Journal of Applied Crystallography 39, no. 2 (March 12, 2006): 230–36. http://dx.doi.org/10.1107/s0021889806004328.

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The crystal structure of monoclinic KLu(WO4)2(KLuW) crystals was determined at room temperature by using single-crystal X-ray diffraction data. The unit-cell parameters werea= 10.576 (7),b= 10.214 (7),c= 7.487 (2) Å, β = 130.68 (4)°, withZ= 4, in space groupC2/c. The unit-cell parameters of KLu1−xYbx(WO4)2were determined in relation to Yb concentration. Vickers micro-indentations were used to study the microhardness of KLuW. The linear thermal expansion tensor was determined and the principal axis with maximum thermal expansion (\alpha_{33}' = 16.72 × 10−6 K−1), X_3', was located 13.51° from thecaxis. The room-temperature optical tensor was studied in the near-infrared (NIR) and visible range. The principal optical axis with maximum refractive index (ng= 2.113),Ng, was located 18.5° from thecaxis at 632.8 nm. Undoped and ytterbium-doped KLuW crystals were grown by the TSSG (top-seeded-solution growth) slow-cooling method. The crystals show {110}, {\bar{1}11}, {010} and {310} faces that basically constitue the habit of the KLuW crystals.

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Pathak, Rahman, Singh, and Kumari. "Sensitivity Enhancement of a Concave Shaped Optical Fiber Refractive Index Sensor Covered with Multiple Au Nanowires." Sensors 19, no. 19 (September 27, 2019): 4210. http://dx.doi.org/10.3390/s19194210.

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In the present paper, a new kind of concave shaped refractive index sensor (CSRIS) exploiting localized surface plasmon resonance (LSPR) is proposed and numerically optimized. The LSPR effect between polaritons and the core guided mode of designed CSRIS is used to enhance the sensing performance. The sensor is characterized for two types of sensing structures coated with gold (Au) film and Au nanowires (AuNWs), respectively. The influence of structural parameters such as the distance (D) of the concave shaped channel (CSC) from the core, the diameter of the nanowire (dn) and the size (s) of the CSC are investigated here. In comparison to Au film, the AuNWs are shown to significantly enhance the sensitivity and the performance of the designed sensor. An enhanced sensitivity of 4471 nm/RIU (refractive index unit) is obtained with AuNWs, for a wide range of analytes refractive index (na) varying between 1.33 to 1.38. However, for conventional Au film; the sensitivity of 808.57 nm/RIU is obtained for the same range of analytes.

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Liang, Kai, and Hui Zhao. "First-principles study of electronic and optical properties of Sr2ZnN2 under pressure." Modern Physics Letters B 30, no. 10 (April 20, 2016): 1650139. http://dx.doi.org/10.1142/s0217984916501396.

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First-principles calculations of ternary Sr2ZnN2 compound using density-functional theory (DFT) method within the generalized gradient approximation (GGA) has been performed. Based on the optimized structural parameter, the electronic properties and optical properties have been researched. The calculated lattice constants are in agreement with the experimental and theoretical results. The electronic structure have been investigated throughout the calculated band structure and density of states (DOS). It shows that this compound belongs to the semiconductors with a band gap of about 0.775[Formula: see text]eV. Furthermore, in order to clarify the optical transition of this material, the optical properties such as dielectric function, absorption coefficient, reflectivity, refractive index and energy-loss function at different pressures of 0, 10 and 20[Formula: see text]GPa in the energy range 0–20[Formula: see text]eV were performed and discussed. It shows that Sr2ZnN2 is a strong anisotropy material and the imaginary part of dielectric function shifts to higher energy region as the pressure increases. The square of calculated static refractive index is equal to static dielectric function, which corresponds to the theory formula. In conclusion, pressure is a effective method to change the electronic structure and optical properties.

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Mohd Fudzi, Faznny, Halimah Mohamed Kamari, Amirah Abd Latif, and Azlan Muhammad Noorazlan. "Linear Optical Properties of Zinc Borotellurite Glass Doped with Lanthanum Oxide Nanoparticles for Optoelectronic and Photonic Application." Journal of Nanomaterials 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/4150802.

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Enhancing the optical properties of glasses for the sake of optical application in various fields is an ongoing challenge in materials science and technology. Thus, the optical properties of zinc borotellurite glass doped with lanthanum oxide nanoparticles (La2O3 NPs) with the chemical composition of {[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}1−x (La2O3 NPs)x, where x = 0.01, 0.02, 0.03, 0.04, and 0.05 molar fraction, have been investigated. Characterization techniques such as x-ray diffraction, Fourier Transform Infrared Spectroscopy, and Ultraviolet-Visible Spectroscopy are employed to yield the structural properties and optical parameter of the glass. The amorphous nature of the fabricated glasses is confirmed with the presence of a broad hump via XRD diffraction pattern. The decreasing amount of high polarizable nonbridging oxygen as the concentration of La2O3 NPs increases has contributed to the increasing trend of energy band gap in the range of 2.70 to 3.52 eV and decreasing value of refractive index between 2.34 and 2.48. The fabricated glasses that have a higher refractive index than the widely used fiber material, pure silica glass, indicate that zinc borotellurite glass doped with lanthanum nanoparticles is a promising material to be applied as optical fibers.

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31

BCHIRI, Y., N. BOUGUILA, M. KRAINI, and S. ALAYA. "ANNEALED In2S3 THIN FILMS PREPARED BY SPRAY TECHNIQUE: REPORT ON THE STRUCTURAL, OPTICAL AND DISPERSION ENERGY PARAMETERS." Surface Review and Letters 26, no. 07 (August 2019): 1850223. http://dx.doi.org/10.1142/s0218625x18502232.

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In2S3 thin films with different S/In molar ratios (from 1.5 to 3.5) were deposited via a spray pyrolysis technique on glass substrates at 340∘C. Then, the obtained films were annealed at the same temperature 400∘C for 2[Formula: see text]h. X-ray diffraction study reveals the formation of cubic [Formula: see text]-In2S3 phase with (400) as preferred orientation. The crystallite size varies in the range 64–97[Formula: see text]nm. Optical analysis exhibits that transmittance in visible and near infrared regions is higher than 65% for all films. The optical band gap varied from 2.58[Formula: see text]eV to 2.67[Formula: see text]eV. The optical parameters (refractive index, extinction coefficient, dielectric constants) were calculated through the transmittance ([Formula: see text]) and reflectance ([Formula: see text]). Dispersion parameters ([Formula: see text], [Formula: see text]), high frequency dielectric constant ([Formula: see text]), refractive index ([Formula: see text]), oscillator length strength ([Formula: see text]), average oscillator wavelength ([Formula: see text]) and optical moments ([Formula: see text]) were determined by Wemple–DiDomenico model. The surface and volume energy losses with photon energy were also calculated. The optical and electrical conductivities were estimated. These properties of In2S3 films are important for photovoltaic applications.

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32

El-Nahass, M. M., H. S. Soliman, and E. A. A. El-Shazly. "Heat Treatment Effect on the Structural and Optical Properties of CdGa2S4 Thin Films." Modern Physics Letters B 17, no. 13n14 (June 20, 2003): 771–82. http://dx.doi.org/10.1142/s0217984903005378.

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CdGa 2 S 4 was prepared in powder form by reacting CdS and Ga 2 S 3. The powder had a tetragonal crystal structure with lattice parameters, a = 0.559 ± 0.005 nm , c = 1.008 ± 0.009 nm and c/a = 1.803. CdGa 2 S 4 films deposited by thermal evaporation of the powder were noncrystalline. After annealing, the CdGa 2 S 4 thin films contain crystals with the tetragonal crystal structure. The optical constants (the refractive index n, the absorption index k and the absorption coefficient α) were determined for CdGa 2 S 4 thin films in the thickness range 170–452 nm. It was found that both n and k are independent of the film thickness and both are slightly different as deposited and annealed films. The refractive index shows anomalous dispersion in the spectral range 300–700 nm. The high frequency dielectric constant ε∞ was determined for the as-deposited and after being annealed films. It was found that ε∞ = 5.12 and 5.52 for the as-deposited and after being annealed films respectively. Graphical representations of (αhν)r = f(hν) yield three linear parts, indicating the existence of two indirect and one direct allowed transitions. The values of [Formula: see text], [Formula: see text] and [Formula: see text] for CdGa 2 S 4 for the as-deposited and annealed films are presented.

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Hussin, N. H., Mohamad Fariz Mohamad Taib, Mohd Hazrie Samat, N. Jon, Oskar Hasdinor Hassan, and Muhd Zu Azhan Yahya. "Study of Structural, Electronic and Optical Properties of Lanthanum Doped Perovskite PZT Using Density Functional Theory." Applied Mechanics and Materials 864 (April 2017): 127–32. http://dx.doi.org/10.4028/www.scientific.net/amm.864.127.

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Ferroelectric materials of lanthanum (La) doped PbZrTiO3 (PLZT) were investigated via first principles study. The structural, electronic and optical properties of PLZT in tetragonal structure (P4mm space group) were performed in the framework of density functional theory (DFT) with generalized gradient approximation (GGA) and local density approximation (LDA) methods. The calculated results of structural properties of PLZT were seen to be approximately close to the experimental data. The results of the electronic part were covered with the calculation of energy band gap and density of states (DOS). The highest valence band (VB) which lies at the Fermi level (EF) was dominated by the O 2p at F point. The conduction band (CB) of PLZT occurred at G point, which was primarily dominated by Ti 3d mixed at Pb and La p-state. Whereas the optical part was covered with the refractive index and absorption. The refractive index, n and the extinction coefficient, k were calculated with respect to photon energy. Those results obtained could be such a good prediction in studying parameters and properties of new materials.

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Kocyigit, Adem, Mehmet Okan Erdal, and Murat Yıldırım. "Effect of Indium Doping on Optical Parameter Properties of Sol–Gel-Derived ZnO Thin Films." Zeitschrift für Naturforschung A 74, no. 10 (September 25, 2019): 915–23. http://dx.doi.org/10.1515/zna-2019-0070.

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AbstractZinc oxide (ZnO) has gained great interest for two decades, and its structural, optical, and electrical properties have been investigated by scientists for technological applications. The optical properties of ZnO provide an opportunity for its application in solar cells, lasers, and light-emitting diodes. We prepared ZnO thin films with various In doping levels by using a spin coating technique, and characterised their morphological and detailed optical properties for optical applications. According to the morphological properties obtained by atomic force microscopy, the film surfaces are homogeneous and the In doping level affects the surface morphology of the films. The optical properties of the films were investigated using an ultraviolet–visible spectrometer, and some optical parameters such as band gap, refractive index, extinction coefficient, single oscillator parameters, real and imaginary functions of the dielectric coefficient, and optical conductivity were calculated and discussed in detail. The various In doping levels affected the optical properties, and the In-doped ZnO thin films can find applications in industry.

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35

Guglielmi, M., A. Martucci, R. M. Almeida, H. C. Vasconcelos, E. M. Yeatman, E. J. C. Dawnay, and M. A. Fardad. "Spinning deposition of silica and silica-titania optical coatings: A round robin test." Journal of Materials Research 13, no. 3 (March 1998): 731–38. http://dx.doi.org/10.1557/jmr.1998.0092.

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A round robin test has been performed on sol-gel processing for the deposition of silica and silica-titania films on silicon substrates by spin-coating. Three solution preparation processes for silica coatings and three for silica-titania coatings were used to prepare samples at each of the participating laboratories. The films have been characterized mainly by thickness (profilometry and ellipsometry measurements), refractive index, porosity, and optical scattering. Different processes gave different thicknesses. Thickness differences were found in films prepared by the same process and by the same deposition parameters, but in different laboratories, when heat-treated at 500 °C. Variations were reduced in samples annealed at 1000 °C. Refractive index and porosity measurements suggest that variations were due to structural differences, particularly porosity. Furthermore, films heat-treated at 500 °C were not completely stabilized, and showed index and porosity variations after six months.

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Wang, Mengmeng, Meng Zhang, Yifei Wang, Ruijuan Zhao, and Shubin Yan. "Fano Resonance in an Asymmetric MIM Waveguide Structure and Its Application in a Refractive Index Nanosensor." Sensors 19, no. 4 (February 15, 2019): 791. http://dx.doi.org/10.3390/s19040791.

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Herein, the design for a tunable plasmonic refractive index nanosensor is presented. The sensor is composed of a metal–insulator–metal waveguide with a baffle and a circular split-ring resonator cavity. Analysis of transmission characteristics of the sensor structures was performed using the finite element method, and the influence of the structure parameters on the sensing characteristics of the sensor is studied in detail. The calculation results show that the structure can realize dual Fano resonance, and the structural parameters of the sensor have different effects on Fano resonance. The peak position and the line shape of the resonance can be adjusted by altering the sensitive parameters. The maximum value of structural sensitivity was found to be 1114.3 nm/RIU, with a figure of merit of 55.71. The results indicate that the proposed structure can be applied to optical integrated circuits, particularly in high sensitivity nanosensors.

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Al-Taa'y, Wasan A., and Bushra A. Hasan. "Structural and optical properties of TiO2:NiO nanoparticles thin films prepare by chemical spray pyrolysis." Iraqi Journal of Physics (IJP) 19, no. 49 (May 18, 2021): 22–31. http://dx.doi.org/10.30723/ijp.v19i49.632.

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The properties of structural and optical of pure and doped nano titanium dioxide (TiO2) films, prepared using chemical spray pyrolysis (CPS) technique, with different nanosize nickel oxide (NiO) concentrations in the range (3-9)wt% have been studied. X-Ray diffraction (XRD) technique where using to analysis the structure properties of the prepared thin films. The results revealed that the structure properties of TiO2 have polycrystalline structure with anatase phase. The parameters, energy gap, extinction coefficient, refractive index, real and imaginary parts were studied using absorbance and transmittance measurements from a computerized ultraviolet visible spectrophotometer (Shimadzu UV-1601 PC) in the wavelengths range (300-800)nm. Optical properties of TiO2 affected by the adding of NiO impurity where the transmittance increased as NiO concentration increased but with more adding the transmittance returned to decrease again. It was found the extinction coefficient, refractive index, real and imaginary parts values decreased with increasing doping percentage up to 7% and then increases occur one more again at 9%. Energy gap values increased after doping with NiO where the values lies in the range was 3.31 to 3.51 eV .

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38

LI, SHUFENG, LI WANG, XUEQIONG SU, YONG PANG, DONGWEN GAO, and XIAOWEI HAN. "EFFECTS OF Co CONCENTRATION ON THE STRUCTURAL AND OPTICAL PROPERTIES OF Zn1−xCoxS FILMS." Surface Review and Letters 27, no. 08 (February 3, 2020): 1950196. http://dx.doi.org/10.1142/s0218625x19501968.

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Amorphous and crystalline Zn[Formula: see text]CoxS ([Formula: see text], 0.3, 0.5) thin films were grown on sapphire (Al2O3) substrates by pulsed laser deposition at substrate temperature of 25∘C and 800∘C, respectively. The X-ray diffraction results show that the crystalline film has a cubic zinc blende structure and the crystalline quality decreased with increasing Co-doping concentration. The X-ray diffraction and X-ray photoelectron spectroscopy spectra reveal that the samples reached an overdoping state at Co-doping concentration of [Formula: see text]. The absorbance of films increases and the absorption edge shifts to longer wave length direction with increasing Co-doping concentration. The redshift of the band gap energy depends on the Co composition associating with the Urbach energy. Furthermore, the refractive index and dielectric constant increase with increasing Co-doping concentration. The dispersion parameters, such as dispersion energy ([Formula: see text]), oscillator energy ([Formula: see text]), static refractive index ([Formula: see text]), static dielectric constant ([Formula: see text]), interband transition strength moments ([Formula: see text] and [Formula: see text]), oscillator strength [Formula: see text] and oscillator wavelength [Formula: see text], have been analyzed by Wemple–DiDomenico single oscillator model. All these parameters were found to be dependent upon the Co-doping concentration in the Zn[Formula: see text]CoxS thin films.

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Liu, Qi-Jun, Zheng-Tang Liu, Li-Ping Feng, and Hao Tian. "First-Principles Study of Electronic Structure and Optical Properties of Tetragonal PbMoO4." ISRN Condensed Matter Physics 2011 (November 3, 2011): 1–7. http://dx.doi.org/10.5402/2011/290741.

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Using the plane-wave ultrasoft pseudopotential technique based on the first-principles density functional theory (DFT), we have studied the structural, electronic, chemical bonding, and optical properties of tetragonal PbMoO4. The obtained structural parameters are in good agreement with experiments. Band structure, density of states, and chemical bonding are calculated and shown. It is found that tetragonal PbMoO4 is an indirect band gap. The dielectric function, refractive index, extinction coefficient, reflectivity, absorption coefficient, loss function, and conductivity function are calculated for radiation up to 20 eV.

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40

Rajesh Kumar, B., and B. Hymavathi. "Effect of oxygen flow rate on structural, electrical and optical properties of zinc aluminum oxide thin films deposited by DC magnetron sputtering -=SUP=-*-=/SUP=-." Журнал технической физики 53, no. 4 (2019): 583. http://dx.doi.org/10.21883/ftp.2019.04.47460.8887.

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AbstractZinc Aluminum Oxide thin films were deposited on glass substrates by reactive DC magnetron sputtering method by varying oxygen flow rates from 1 to 4 sccm. Glancing angle X-ray diffraction patterns ofzinc aluminum oxide thin films exhibits (0 0 2) peak with c-plane preferentially oriented parallel to the substrate. The surface morphology and elemental analysis of the films was observed by field emission scanning electron microscopy attached with energy dispersive X-ray analysis spectroscopy. An average optical transmittance of 83–90% is obtained for the films deposited at various oxygen flow rates. The optical band gap of the films increases from 3.41 to 3.53 eV with the increase of oxygen flow rate due to Burstein–Moss effect. The optical dispersion parameters such as dispersion energy ( E _ d ), oscillator energy ( E _ o ) and static refractive index ( n _ o ) were determined using the Wemple-DiDomenico (W-D) single oscillator model. The nonlinear optical parameters such as optical susceptibility (χ^(1)), third order nonlinear optical susceptibility (χ^(3)) and nonlinear refractive index ( n _2) were also determined.

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41

Rashad, M., E. F. M. El-Zaidia, S. E. AL Garni, and A. A. A. Darwish. "Quantum Confinement Observation of Milled Potassium Chloride." Nano 14, no. 06 (June 2019): 1950067. http://dx.doi.org/10.1142/s179329201950067x.

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Potassium chloride (KCl) nanoparticles were synthesized by ball milling technique with different milling time. The effect of milling time on structural and optical properties was investigated. The structural properties of the purchased samples are characterized by Raman spectroscopy, scanning electron microscope and X-ray diffraction techniques. The Raman spectroscopy of the KCl hints at an excellent alloying behavior of those compounds and a preferred crystal structure for certain composition. The optical band is calculated by analyzing the spectral behavior of the absorption coefficient in the absorption region which revealed direct transitions. The value optical band increases (4.02–5.11[Formula: see text]eV) with increasing milling time (0–15[Formula: see text]h) due to quantum confinement after the ball milling process. The refractive and absorption indices were calculated for all samples. The model of Wemple–DiDomenico was used to calculate the dispersion parameters. The nonlinear susceptibility of the third order and the nonlinear refractive index were calculated by linear optical parameters using the generalized Miller rule.

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Hussin, N. H., M. F. M. Taib, N. A. Johari, F. W. Badrudin, O. H. Hassan, and M. Z. A. Yahya. "Establishment of Structural and Elastic Properties of Titanate Compounds Based on Pb, Sn and Ge by First-Principles Calculation." Applied Mechanics and Materials 510 (February 2014): 57–62. http://dx.doi.org/10.4028/www.scientific.net/amm.510.57.

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Structural, electronic, and optical properties of PbTiO3, SnTiO3, and GeTiO3 tetragonals (P4mm, 99 space group) were investigated using density functional theory as implemented in pseudo-potential plane wave in CASTEP computer code. The calculated equilibrium lattice parameter, electronic band structure, and optical properties for PbTiO3 (reference compound) are in good agreement with the available experiment data. The result also shows that GeTiO3 has a higher tetragonality (c/a=1.18) compared with SnTiO3 (c/a=1.15) and PbTiO3 (c/a=1.05). Calculations of the elastic constants of PbTiO3, SnTiO3, and GeTiO3 tetragonals show that they are mechanically stable. The electronic band structure shows that PbTiO3 has higher indirect band gap at X-G compared with SnTiO3 and GeTiO3, as explained in detail by the optical properties of ATiO3 (A=Pb, Sn, Ge) through the refractive index and absorption coefficient.

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43

Biswas, Mitali, Mehnaz Sharmin, Chitra Das, Jibon Poddar, and Shamima Choudhury. "Structural and Optical Characterization of Magnesium Doped Zinc Oxide Thin Films Deposited by Spray Pyrolysis." Dhaka University Journal of Science 64, no. 1 (June 28, 2016): 1–6. http://dx.doi.org/10.3329/dujs.v64i1.28516.

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Pure and magnesium (Mg) doped zinc oxide (ZnO) thin films were prepared onto clean glass substrate by spray pyrolysis (SP) technique at the substrate temperature of 300°C. Various optical parameters such as absorption co-efficient, band gap energy, refractive index, extinction coefficient of the thin films were studied using UV-VIS-NIR spectrophotometer in the photon wavelength range of 300-2500 nm. Optical band gap increased from 3.24 to 3.46 eV with the increase of Mg concentration from 0 to 40%. Transmittance and refractive index of the Mg doped ZnO thin films decreased due to the increase of Mg concentration. The EDX spectra confirmed the increase of Mg and consequent reduction in Zn content in the Mg doped ZnO thin films. Pure and Mg- doped ZnO films were annealed at 425°C for 1 hour. X-ray diffraction (XRD) study of the annealed films showed hexagonal type of polycry-stalline structure with the preferred orientation along (101) plane with some other peaks (100), (002), (102), (110), (103) and (112). From the XRD patterns it was found that grain size decreased from 63.45 to 36.56 nm, lattice constant _ and c remained almost constant with Mg doping concentration.Dhaka Univ. J. Sci. 64(1): 1-6, 2016 (January)

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44

Bhuiyan, M. R. A., M. A. H. Miah, and J. Begum. "Substrate Temperature Effect on the Structural and Optical Properties of Znse Thin Films." Journal of Bangladesh Academy of Sciences 36, no. 2 (December 15, 2012): 233–40. http://dx.doi.org/10.3329/jbas.v36i2.12969.

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Zinc selenide (ZnSe) thin films were deposited on to chemically and ultrasonically cleaned glass substrates at different substrate temperatures from room temperature to 200°C keeping the thickness fixed at 300 nm by using thermal evaporation method in vacuum. The structural properties of the films were ascertained by X-ray diffraction (XRD) method utilizing a diffractometer. The optical properties were measured in the photon wavelength ranging between 300 and 2500 nm by using a UV-VIS-NIR spectrophotometer. The XRD patterns reveal that the films were polycrystalline in nature exhibiting f.c.c zincblende structure with average lattice parameter, a = 5.6873Å. The grain size, strain and dislocation densities of the films have bee calculated. The optical transmittance and reflectance were utilized to compute the absorption coefficient, band gap energy and refractive index of the films. The band gap energy of the films was extracted from the absorption spectra. The direct band gap energy of the films slightly increases with substrate temperature.DOI: http://dx.doi.org/10.3329/jbas.v36i2.12969Journal of Bangladesh Academy of Sciences, Vol. 36, No. 2, 233-240, 2012

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45

Rincón, Carlos A. Durante, Larissa T. Durán, Josefa Estévez Medina, Jaime A. Castro, Máximo León, and Jose R. Fermín. "Structural and optical properties of AgIn5S8." International Journal of Modern Physics B 31, no. 31 (December 10, 2017): 1750246. http://dx.doi.org/10.1142/s0217979217502460.

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Compounds of the chalcogenide family Ag–In–VI (VI = S, Se, Te) are interesting materials due to their stoichiometric stability and potential application in nonlinear optics and solar cells. A polycrystalline ingot of AgIn5S8, an ordered vacancy semiconductor, was prepared by direct fusion of the stoichiometric mixture of the elements in an evacuated quartz ampoule. The presence of a single phase with cubic structure was confirmed by X-ray powder diffraction at room temperature. The lattice parameter, [Formula: see text], was calculated, giving 10.821750 Å. Samples in evacuated quartz ampoules were used to perform Differential Thermal Analysis measurements, showing congruent melting at 1110[Formula: see text]C. Transmittance and reflectivity measurements were used to calculate the absorption coefficient [Formula: see text]. From the plot of ([Formula: see text])2 versus [Formula: see text], two direct transitions are observed at 1.25 eV and 1.88 eV. While the higher energy direct transition has been observed by other authors, the direct nature of the lower energy transition was confirmed from the fitting of the plot of the reflectivity versus 1/[Formula: see text] between 0.53 eV[Formula: see text] (1.89 eV) and 0.55 eV[Formula: see text] (1.82 eV), obtaining a value of 1.29 eV. The real refractive index [Formula: see text] and the high-frequency dielectric constant [Formula: see text] were also obtained from the fit of the reflectivity, resulting to be 2.68 and 7.2, respectively.

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Feng, Guo Jin, Ping Li, Yu Wang, Cheng Li, and Li Zhao. "Reflectance of Micro-Structural Material on Au." Materials Science Forum 663-665 (November 2010): 154–57. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.154.

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The high absorption characteristics, the complex mechanism and the great potential application in detectors of micro-structural material aroused extensive attention. In order to understand the impact of the micro-structure, the optical simulation method based on Monte Carlo is used for reflection characteristics of micro-structural material with the cell of pyramid construction. In this simulation, the body material is made of gold, which can avoid the effect of tranmittance, with a number of 400 cells. The bottom square of each structure is 50×50 µm, and the height of cells is adjustable. Then the relationship between the height and reflectance can be built up. However, a very complex relationship between the reflectance and the input parameters, including refractive index, extinction coefficient and the structure of the material is showed from simulation result. Generally, the reflectance decreases while the height increases.

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Rahim, Tariq, and Jia Dong Xu. "Analysis of Double Layer Cross Strips with Chiral Configuration Exhibiting Negative Refractive Index." International Journal of Engineering Research in Africa 22 (February 2016): 128–34. http://dx.doi.org/10.4028/www.scientific.net/jera.22.128.

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Metamaterials composed of metallic strips on both side of the substrate are analyzed at microwave frequencies. The rectangular shaped metallic foils are rotated by 90o with respect to their adjacent metal strip on each side of the substrate. The twist angle between the cross strips on opposite sides of substrate is 40o. The proposed structure exhibits the properties of chiral medium such as optical activity and circular dichroism due to their cross coupling between the electric and magnetic fields. The rectangular shaped chiral objects can be easily fabricated on double side substrate. Both transmission and reflection resonances are illustrated. The chiral configuration of this metamaterial structure is analyzed in commercial software Computer Simulation Technology (CST) microwave studio and negative refractive index is observed. Moreover, other electromagnetic structural parameters such as chirality, optical activity and polarization effect are discussed.

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Hamdalla, Taymour A., Taha A. Hanafy, and Ashraf E. Bekheet. "Influence of Erbium Ions on the Optical and Structural Properties of Polyvinyl Alcohol." Journal of Spectroscopy 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/204867.

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Polyvinyl alcohol (PVA) films doped with erbium chloride (ErCl3) have been prepared by casting from their aqueous solutions. The structure of the doped samples as well as the interactions between the host PVA and Er+3was investigated using FTIR spectroscopy. The optical measurement was recorded at room temperature in the range from 200 nm to 2000 nm. FTIR measurements revealed that Er+3forms complex configuration within the PVA structure. PVA doped with 9 wt% of ErCl3exhibits energy gap and refractive index of 5.1 eV and 1.72, respectively. The effect of the doping increment of ErCl3on the optical parameters has been discussed.

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Liang, Han, Tao Shen, Yue Feng, Hongchen Liu, and Wei Han. "A D-Shaped Photonic Crystal Fiber Refractive Index Sensor Coated with Graphene and Zinc Oxide." Sensors 21, no. 1 (December 24, 2020): 71. http://dx.doi.org/10.3390/s21010071.

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A surface plasmon resonance (SPR) sensor based on a D-shaped photonic crystal fiber (PCF) with an uncomplicated structure is proposed to detect the change of refractive index of liquid analytes, and numerical simulation is carried out by the finite element method (FEM). Using silver as the plasmonic metal, the performances of the SPR-PCF sensor coated with a graphene layer and zinc oxide (ZnO) layer were assessed. The sensor designed is only coated with material on the polished surface, which makes the sensor production uncomplicated and solves the problems of filling material in the hole and coating on the hole wall. The effects of structural parameters such as graphene layer thickness, silver layer thickness, ZnO thickness, lattice spacing and manufacturing tolerance of blowhole diameter on the sensor performance were numerically simulated. The numerical results show that the sensitivity of the SPR-PCF sensor coated with 25 nm ZnO is highest in the ZnO thickness range from 10 to 25 nm. In the refractive index range of 1.37–1.41 for liquid analyte, the maximum sensitivity and corresponding resolution reach 6000 nm/RIU and 1.667 × 10−5, respectively. In addition, the sensor has good stability and high structural tolerance under the tolerance of ±5% of blowhole diameter. This work has wide application value in the detection of biochemical analytes, water pollution monitoring, food quality, and medical diagnosis.

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50

Lu, Ziqing, Qin Han, Han Ye, Shuai Wang, and Feng Xiao. "Manufacturing Tolerance Analysis of Deep-Ridged 90° Hybrid Based on InP 4 × 4 MMI." Photonics 7, no. 2 (April 3, 2020): 26. http://dx.doi.org/10.3390/photonics7020026.

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An optical 90° hybrid based on an InGaAsP/InP deep-ridged 4 × 4 multimode interference (MMI) coupler is proposed and fabricated. Manufacturing tolerances on structural parameters of the 90° hybrid including multimode waveguide width and length, waveguide core thickness, and refractive index are analyzed over the whole C-band using a three-dimensional beam propagation method (3D BPM). The simulation results show that the 90° hybrid is insensitive to the interference length with a deviation of 10 μm. However, the width fluctuations produce far stronger performance variations than length fluctuations. The common-mode rejection ratios (CMRRs) are always above 40 dB, and the phase error (PE) is always below 2.5° with the fluctuations of the refractive index by 0.01 and the thickness by 0.1 μm of the core layer. The fabricated device exhibited a quadrature phase response with a high common-mode rejection ratio of more than 25 dB and a small phase error of less than 5° from 1545 nm to 1560 nm.

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Journal articles on the topic 'Structural parameter of refractive index'

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