Articles de revues : « Red detuned optical lattices »

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Hou, Xiaokai, Shuo Liu, Xin Wang, Feifei Lu, Jun He et Junmin Wang. « Suppression of laser beam’s polarization and intensity fluctuation via a Mach–Zehnder interferometer with proper feedback ». AIP Advances 13, n^o 1 (1 janvier 2023) : 015218. http://dx.doi.org/10.1063/5.0133775.

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Long ground-Rydberg coherence lifetime is interesting for implementing high-fidelity quantum logic gates, many-body physics, and other quantum information protocols. However, the potential well formed by a conventional far-off-resonance red-detuned optical-dipole trap that is attractive for ground-state cold atoms is usually repulsive for Rydberg atoms, which will result in the rapid loss of atoms and low repetition rate of the experimental sequence. Moreover, the coherence time will be sharply shortened due to the residual thermal motion of cold atoms. These issues can be addressed by a one-dimensional magic lattice trap, which can form a deeper potential trap than the traveling wave optical dipole trap when the output power is limited. In addition, these common techniques for atomic confinement generally have certain requirements for the polarization and intensity stability of the laser. Here, we demonstrated a method to suppress both the polarization drift and power fluctuation only based on the phase management of the Mach–Zehnder interferometer for a one-dimensional magic lattice trap. With the combination of three wave plates and the interferometer, we used the instrument to collect data in the time domain, analyzed the fluctuation of laser intensity, and calculated the noise power spectral density. We found that the total intensity fluctuation comprising laser power fluctuation and polarization drift was significantly suppressed, and the noise power spectral density after closed-loop locking with a typical bandwidth of 1–3000 Hz was significantly lower than that under the free running of the laser system. Typically, at 1000 Hz, the noise power spectral density after locking was about 10 dB lower than that under the free running of a master oscillator power amplifier system. The intensity–polarization control technique provides potential applications for atomic confinement protocols that demand fixed polarization and intensity.

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Winoto, S., Marshall DePue, Nathan Bramall et David Weiss. « Laser cooling at high density in deep far-detuned optical lattices ». Physical Review A 59, n^o 1 (janvier 1999) : R19—R22. http://dx.doi.org/10.1103/physreva.59.r19.

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Piest, B., V. Vollenkemper, J. Böhm, A. Herbst et E. M. Rasel. « Red- and blue-detuned magneto-optical trapping with liquid crystal variable retarders ». Review of Scientific Instruments 93, n^o 2 (1 février 2022) : 023202. http://dx.doi.org/10.1063/5.0071619.

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Wang Cheng, Xu Peng, He Xiao-Dong, Wang Jin et Zhan Ming-Sheng. « Transferring single-atoms between two red-detuned far-off-resonance optical dipole traps ». Acta Physica Sinica 61, n^o 20 (2012) : 203701. http://dx.doi.org/10.7498/aps.61.203701.

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Kudo, Tetsuhiro, Hajime Ishihara et Hiroshi Masuhara. « Resonance optical trapping of individual dye-doped polystyrene particles with blue- and red-detuned lasers ». Optics Express 25, n^o 5 (21 février 2017) : 4655. http://dx.doi.org/10.1364/oe.25.004655.

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Pan, Deng, Hongxing Xu et F. Javier García de Abajo. « Rotational Doppler cooling and heating ». Science Advances 7, n^o 2 (janvier 2021) : eabd6705. http://dx.doi.org/10.1126/sciadv.abd6705.

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Doppler cooling is a widely used technique to laser cool atoms, molecules, and nanoparticles by exploiting the Doppler shift associated with translational motion. The rotational Doppler effect arising from rotational coordinate transformation should similarly enable optical manipulation of the rotational motion of nanosystems. Here, we show that rotational Doppler cooling and heating (RDC and RDH) effects embody rich and unexplored physics, including an unexpected strong dependence on particle morphology. For geometrically constrained particles, cooling and heating are observed at red- or blue-detuned laser frequencies relative to particle resonances. In contrast, for nanosystems that can be modeled as solid particles, RDH appears close to resonant illumination, while detuned frequencies produce cooling of rotation. We further predict that RDH can lead to optomechanical spontaneous chiral symmetry breaking, where an achiral particle under linearly polarized illumination starts spontaneously rotating. Our results open up new exciting possibilities to control the rotational motion of nanosystems.

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Li, Xiaoxia, Jingyan Li, Xuxin Cheng et Guang-an Li. « Nonreciprocal transmission in a four-mode cavity magnonics system ». Laser Physics Letters 19, n^o 9 (10 août 2022) : 095208. http://dx.doi.org/10.1088/1612-202x/ac85e9.

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Abstract We propose a scheme to create optical nonreciprocal transmission in a double-cavity magnonics system, where one yttrium iron garnet sphere is placed in one of the cavities and a mechanical oscillator is shared by the coupled double microwave cavities. By manipulating the magnon–microwave photon coupling, we reveal the nonreciprocal propagation of electromagnetic fields at microwave frequencies in red and blue-detuned regimes. Furthermore, the nonreciprocal isolation ratio and group delay are analyzed. This scheme can inspire methods for constructing nonreciprocal devices.

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Wang, Zheng Ling, Ming Zhou, Wei Zhang, Chuan Yu Gao et Guo Rong Cao. « Nanoscale Trap for Isolated Cold Atoms by the Nanoscale Solid-State System ». Advanced Materials Research 304 (juillet 2011) : 263–67. http://dx.doi.org/10.4028/www.scientific.net/amr.304.263.

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We propose a novel scheme to generate nanoscale optical trap for cold atoms near the tapered Ag nanotip, in which we take a microdisk cavity near the nanoscale trap and form a nanoscale solid-state system to realize the loading of the isolated cold atoms. We calculate the field distribution by the FDTD method near the nanotip, and discuss the intensity, the optical potential and van der Waals potential as well as the dipole force for 87Rb atoms. We find that the total potential and dipole force can form an attracting nanoscale trap for cold atoms with red-detuned field and it can realize the effective trapping and manipulation of the isolated atoms, which can enable efficient fluorescence photon collection and strong coupling in the coupled optical fiber.

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Yang, Qiulu, Dan Lu, Yiming He, Daibing Zhou et Lingjuan Zhao. « High Optical Feedback Tolerance of a Detuned DBR Laser for 10-Gbps Isolator-Free Operation ». Photonics 10, n^o 1 (30 décembre 2022) : 38. http://dx.doi.org/10.3390/photonics10010038.

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The optical feedback tolerance (OFT) of a distributed Bragg reflector (DBR) laser was investigated experimentally. The static and modulation performance of the DBR laser under optical feedback was examined by evaluating its relative intensity noise (RIN) and bit error rate (BER). It is shown that the OFT of the DBR laser is closely related to its peak wavelength detuning relative to the Bragg wavelength. A high tolerance to optical feedback was demonstrated, both in the continuous wave (CW) and the direct modulation (DM) states, when the DBR laser was red-detuned relative to the Bragg wavelength. The excess RIN induced by optical feedback was well suppressed to a level of −140 dB/Hz at a feedback level of −9 dB in the CW state. In a 10 Gbps direct modulation state, bit error rates (BER) below 1 × 10−9 and 3 × 10−7 were obtained under a feedback level of −15 dB and −9 dB, respectively, for the case of back-to-back transmission. After 20 km fiber transmission, the BER still maintained below 1 × 10−7 under a feedback level of −15 dB, with a power penalty of less than 1 dB.

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He, Xiaodong, Shi Yu, Peng Xu, Jin Wang et Mingsheng Zhan. « Combining red and blue-detuned optical potentials to form a Lamb-Dicke trap for a single neutral atom ». Optics Express 20, n^o 4 (31 janvier 2012) : 3711. http://dx.doi.org/10.1364/oe.20.003711.

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Ram, S. P., S. R. Mishra, S. K. Tiwari et S. C. Mehendale. « Note : Investigation of atom transfer using a red-detuned push beam in a double magneto-optical trap setup ». Review of Scientific Instruments 82, n^o 12 (décembre 2011) : 126108. http://dx.doi.org/10.1063/1.3670356.

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Mantashyan, Paytsar, Rafael Drampyan, Jeroen Beeckman, Oliver Willekens et Kristiaan Neyts. « Optical induction of Bessel-like lattices in methyl-red doped liquid crystal cells ». Optics Communications 338 (mars 2015) : 467–72. http://dx.doi.org/10.1016/j.optcom.2014.11.011.

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Sun, Rui, Xin Wang, Kong Zhang, Jun He et Junmin Wang. « Influence of Laser Intensity Fluctuation on Single-Cesium Atom Trapping Lifetime in a 1064-nm Microscopic Optical Tweezer ». Applied Sciences 10, n^o 2 (16 janvier 2020) : 659. http://dx.doi.org/10.3390/app10020659.

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An optical tweezer composed of a strongly focused single-spatial-mode Gaussian beam of a red-detuned 1064-nm laser can confine a single-cesium (Cs) atom at the strongest point of the light intensity. We can use this for coherent manipulation of single-quantum bits and single-photon sources. The trapping lifetime of the atoms in the optical tweezers is very short due to the impact of the background atoms, the parametric heating of the optical tweezer and the residual thermal motion of the atoms. In this paper, we analyzed the influence of the background pressure, the trap frequency of optical tweezers and the laser intensity fluctuation of optical tweezers on the atomic trapping lifetime. Combined with the external feedback loop based on an acousto-optical modulator (AOM), the intensity fluctuation of the 1064-nm laser in the time domain was suppressed from ±3.360% to ±0.064%, and the suppression bandwidth in the frequency domain reached approximately 33 kHz. The trapping lifetime of a single-Cs atom in the microscopic optical tweezers was extended from 4.04 s to 6.34 s.

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Plewa, Julian, et T. Juestel. « Synthesis and Optical Characterization of Pr³⁺ Doped UV Emitting Luminescent Ceramics ». Materials Science Forum 636-637 (janvier 2010) : 344–47. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.344.

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UV emitting luminescent materials are of strong interest for UV emitting fluorescent lamps driven by a Hg low-pressure or a by Xe excimer discharge. Pr3+ doped host lattices exhibit efficient UV emission upon deep UV excitation, if the site of the host lattice, where Pr3+ is located, is suitable for this purpose. This work deals with Pr3+ activated VUV ceramic luminophores, i.e. materials, which show efficient luminescence upon 160 nm excitation. As host lattices for the potentially UV emitting Pr3+ ion aluminates and silicates have been studied. All samples were prepared by conventional mix and fire synthesis techniques with metal oxides as starting materials. Firstly, powder samples were annealed between 1000 and 1700 °C and secondly, ceramic samples were repeatedly thermally treated at similar temperatures after pressing. It is demonstrated that translucent ceramics show mainly UV luminescence upon deep UV excitation, while excitation by a blue 450 nm LED results in green to red luminescence with a similar decay time as observed for single crystals.

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Prime, E. J., J. A. Behr et M. R. Pearson. « Loading of a far off-resonance dipole force trap for stable 39K ». Canadian Journal of Physics 85, n^o 1 (1 janvier 2007) : 1–12. http://dx.doi.org/10.1139/p07-010.

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A useful tool that can achieve a high level of spin polarization is a circularly polarized far off-resonance dipole force trap (CFORT). This work is the first step in its development; building the necessary components to successfully load stable 39K into a linearly polarized far off-resonance trap (FORT) from a magneto-optical trap, where the atoms are precooled to a temperature of 400 μK. The FORT consists of 700 mW of light from a titanium–sapphire ring laser, focused with a 200 mm achromatic lens to a waist of 35 μm. The light is detuned between 1 and 20 nm to the red of the D1 transition and this gives rise to trap depths in the region of a few milliKelvin. A characterization of the FORT's loading efficiency and lifetime as a function of FORT beam detuning, power, and ellipticity are studied. PACS Nos.: 32.80.Pj, 23.40.–s, 39.25.+k

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Badaut, D., G. Besson, A. Decarreau et R. Rautureau. « Occurrence of a ferrous, trioctahedral smectite in Recent sediments of Atlantis II Deep, Red Sea ». Clay Minerals 20, n^o 3 (septembre 1985) : 389–404. http://dx.doi.org/10.1180/claymin.1985.020.3.09.

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AbstractA trioctahedral, ferrous smectite has been located in the uppermost deposits of Atlantis II Deep, SW basin, Red Sea. This clay is very unstable when removed from its environment of formation and, for example, oxidizes during desiccation under laboratory conditions. Only X-ray transmission diffraction study of the mud itself demonstrates the trioctahedral character of the clay. Electron-optical investigation shows that oxidation within the octahedral sheet creates a juxtaposition of dioctahedral and trioctahedral sub-lattices in the same particle. Ferrous smectite authigenesis is located near the hydrothermal spring outlets of the Atlantis II Deep.

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Singh, Devender, Vijeta Tanwar, Shri Bhagwan, Vandna Nishal, Suman Sheoran, Sonika Kadyan, Anura P. Samantilleke et Pratap Singh Kadyan. « Synthesis and Optical Characterization of Europium Doped MY2O4 (M = Mg, Ca, and Sr) Nanophosphors for Solid State Lightening Applications ». Indian Journal of Materials Science 2015 (17 août 2015) : 1–8. http://dx.doi.org/10.1155/2015/845065.

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Trivalent europium doped yttriate nanophosphors were synthesized by rapid facile gel combustion technique. The photoluminescence (PL) properties of these Eu3+ activated MY2O4 (M = Mg, Ca, and Sr) nanophosphors showed red luminescence and exhibited excellent emission properties in their respective regions of color coordinates. Based on the excitation wavelengths multiple emission peaks were obtained. The main peak in the emission spectra was ascribed to 5D0→7F2 transition of Eu3+ ion. The structural and morphological studies were performed by the measurements of X-ray diffraction profiles, scanning electron microscope (SEM) images, and transmission electron microscope (TEM) micrographs. Furthermore, the effects of additional heating on the different host lattices of these phosphors were also studied.

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Liu Qian, 刘乾, 谢昱 Xie Yu, 李琳 Li Lin, 梁昂昂 Liang Ang’ang, 李文文 Li Wenwen, 程鹤楠 Cheng Henan, 方苏 Fang Su, 刘亮 Liu Liang, 汪斌 Wang Bin et 吕德胜 Lü Desheng. « 基于红失谐高斯光束的冷原子束流长距离传输 ». Acta Optica Sinica 41, n^o 21 (2021) : 2102001. http://dx.doi.org/10.3788/aos202141.2102001.

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Zakria, M., Taj Muhammad Khan, Abbas Nasir et Arshad Mahmood. « Annealing-induced effects on structural and optical properties of Cd1−xZnxS thin films for optoelectronic applications ». Materials Science-Poland 33, n^o 4 (1 décembre 2015) : 677–84. http://dx.doi.org/10.1515/msp-2015-0096.

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AbstractCd1−xZnxS thin films of variable compositions (x = 0.2, 0.4, 0.6, 0.8) were deposited on glass at room temperature by thermal evaporation process. The prepared samples were annealed at two different temperatures (300 °C, 400 °C) for 1 hour in ambient air. The effects of post-annealing on the structural and optical characteristics were investigated using X-ray diffraction (XRD), spectrophotometry, and Raman spectroscopy (RS) methods. XRD studies suggested that the annealed and as-deposited samples belong to wurtzite structure for all Zn concentrations with a preferential orientation along (002) plane. Spectrophotometry analysis of the samples revealed that the energy band gap decreased with annealing temperature. RS investigated different phonon bands and crystalline phases. Two longitudinal optical phonon modes (1-LO, 2-LO) corresponding to monophase hexagonal structure were observed for all Cd1−xZnxS samples. The observed red-shift and anti-symmetrical nature of the 1-LO phonon mode can be associated with annealing, while the overall blue-shift, except for x ⩽ 0.6, was caused by the structural disorders in periodic Cd atomic sub-lattices and broken translational symmetry. The spectroscopic results were strengthened by the XRD studies and their results are consistent.

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McNamara, Maria E., Vinod Saranathan, Emma R. Locatelli, Heeso Noh, Derek E. G. Briggs, Patrick J. Orr et Hui Cao. « Cryptic iridescence in a fossil weevil generated by single diamond photonic crystals ». Journal of The Royal Society Interface 11, n^o 100 (6 novembre 2014) : 20140736. http://dx.doi.org/10.1098/rsif.2014.0736.

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Nature's most spectacular colours originate in integumentary tissue architectures that scatter light via nanoscale modulations of the refractive index. The most intricate biophotonic nanostructures are three-dimensional crystals with opal, single diamond or single gyroid lattices. Despite intense interest in their optical and structural properties, the evolution of such nanostructures is poorly understood, due in part to a lack of data from the fossil record. Here, we report preservation of single diamond ( Fd -3 m ) three-dimensional photonic crystals in scales of a 735 000 year old specimen of the brown Nearctic weevil Hypera diversipunctata from Gold Run, Canada, and in extant conspecifics. The preserved red to green structural colours exhibit near-field brilliancy yet are inconspicuous from afar; they most likely had cryptic functions in substrate matching. The discovery of pristine fossil examples indicates that the fossil record is likely to yield further data on the evolution of three-dimensional photonic nanostructures and their biological functions.

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Zhou, Shi Wen, Jian Liu, Ping Peng et Wen Qin Chen. « Effects of S/Ce-codoping on electronic structures and optical properties of anatase TiO2 from density functional theory calculations ». Modern Physics Letters B 29, n^o 35n36 (30 décembre 2015) : 1550249. http://dx.doi.org/10.1142/s0217984915502498.

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The electronic and optical properties of S- and/or Ce-(co)doped anatase titanium dioxide (TiO2) are investigated using density functional theory plus U (DFT[Formula: see text]U) calculations. The optimized total energy suggests that TiO2 codoping by Ce and S favours the configuration of one substitutional Ce atom occupied on a Ti site with one substitutional S atom either on its nearest neighboring O or Ti site. The calculated results show that all doping configurations exhibit remarkable red-shift and excellent photocatalytic properties compared with pure TiO2. These reinforced features can mainly be ascribed to the appearance of S [Formula: see text] states in the top of valence band (VB) and Ce [Formula: see text] states in the bottom of conduction band (CB) as well as the contribution from the increasing octahedral dipole moments. The synergetic effects of cationic Ce and anionic S can extend optical absorption edge, which results in higher absorption coefficient in the visible light region than that of the anionic S monodoping and cationic Ce monodoping case; in the same time, decreasing the codoping concentration leads to reduced optical absorption. Additionally, Ce and S as cations incorporating into TiO2 lattices can induce stronger redox potential with a lower defect formation energy under O-rich condition compared with other doping systems.

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Li, Yunqi, Xinwei Wang, Ning Zhang, Xuecheng Wei et Junxi Wang. « Improving the incorporation of indium component for InGaN-based green LED through inserting photonic crystalline in the GaN layer ». Journal of Semiconductors 43, n^o 7 (1 juillet 2022) : 072801. http://dx.doi.org/10.1088/1674-4926/43/7/072801.

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Abstract We report on the effect of inserted photonic crystalline (Ph-C) in the GaN epitaxial layer on the incorporation of the indium component for the InGaN-based green LED. The adoption of Ph-C in the GaN layer shifted the Raman peak value of E2 mode of GaN to lower frequency and resulted in a tensive stress relief. The stress relief can be attributed to strained lattices restoring in the matrix of Ph-C and the GaN pseudo-epitaxy over the air-void of the Ph-C. Moreover, the HRXRD rocking curves and AFM results show that the insertion of Ph-C also improves the crystal quality. With the inserted Ph-C, the indium component in the multiple quantum wells of the green LED (Ph-C LED) was enhanced. This resulted in a 6-nm red-shift of the peak wavelength. Furthermore, the LOP of the Ph-C LED was enhanced by 10.65% under an injection current of 20 mA.

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Aritonang, Anthoni B., Eka Pratiwi, Warsidah Warsidah, S. I. Nurdiansyah et R. Risko. « Fe-doped TiO2/Kaolinite as an Antibacterial Photocatalyst under Visible Light Irradiation ». Bulletin of Chemical Reaction Engineering & ; Catalysis 16, n^o 2 (2 avril 2021) : 293–301. http://dx.doi.org/10.9767/bcrec.16.2.10325.293-301.

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In this work, undoped and Fe-doped TiO2 immobilized on kaolinite surface was successfully synthesized by sol-gel method with various Fe concentrations (0.05, 0.125, and 0.25 wt%). The eﬀects of Fe doping into TiO2 lattice were thoroughly investigated by a diffuse reflectance UV-visible (DRS) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The optical band gap of undoped and Fe-doped TiO2/kaolinite is red shifted with respect to the incorporation of Fe3+ into the structure of TiO2 resulted band gap. The FTIR spectra shows a shift of peak at the wave number at 586 cm−1 and 774 cm−1 which is attribute of the Fe−O vibration as an indication of the formation of Fe-TiO2 bonds. Incorporation of Fe3+ cation into the TiO2 lattice replacing the Ti4+ ions, which induced a perturbation in anatase crystal structure, causes the change in the distance spacing of the crystal lattices dhkl(101) of 8.9632 to 7.9413. The enhanced photocatalytic performance was observed for Fe-doped TiO2/kaolinite compared with TiO2/kaolinite with respect to Escherichia coli growth inhibition in solution media under visible light irradiation. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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Zhang, Binbin, Yu Luo, Chaohuang Mai, Lan Mu, Miaozi Li, Junjie Wang, Wei Xu et Junbiao Peng. « Effects of ZnMgO Electron Transport Layer on the Performance of InP-Based Inverted Quantum Dot Light-Emitting Diodes ». Nanomaterials 11, n^o 5 (9 mai 2021) : 1246. http://dx.doi.org/10.3390/nano11051246.

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An environment-friendly inverted indium phosphide red quantum dot light-emitting diode (InP QLED) was fabricated using Mg-doped zinc oxide (ZnMgO) as the electron transport layer (ETL). The effects of ZnMgO ETL on the performance of InP QLED were investigated. X-ray diffraction (XRD) analysis indicated that ZnMgO film has an amorphous structure, which is similar to zinc oxide (ZnO) film. Comparison of morphology between ZnO film and ZnMgO film demonstrated that Mg-doped ZnO film remains a high-quality surface (root mean square roughness: 0.86 nm) as smooth as ZnO film. The optical band gap and ultraviolet photoelectron spectroscopy (UPS) analysis revealed that the conduction band of ZnO shifts to a more matched position with InP quantum dot after Mg-doping, resulting in the decrease in turn-on voltage from 2.51 to 2.32 V. In addition, the ratio of irradiation recombination of QLED increases from 7% to 25% using ZnMgO ETL, which can be attributed to reduction in trap state by introducing Mg ions into ZnO lattices. As a result, ZnMgO is a promising material to enhance the performance of inverted InP QLED. This work suggests that ZnMgO has the potential to improve the performance of QLED, which consists of the ITO/ETL/InP QDs/TCTA/MoO3/Al, and Mg-doping strategy is an efficient route to directionally regulate ZnO conduction bands.

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Yu, Deshui, et Frank Vollmer. « Microscale whispering-gallery-mode light sources with lattice-confined atoms ». Scientific Reports 11, n^o 1 (6 juillet 2021). http://dx.doi.org/10.1038/s41598-021-93295-5.

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AbstractMicrolasers, relying on the strong coupling between active particles and optical microcavity, exhibit fundamental differences from conventional lasers, such as multi-threshold/thresholdless behavior and nonclassical photon emission. As light sources, microlasers possess extensive applications in precision measurement, quantum information processing, and biochemical sensing. Here we propose a whispering-gallery-mode microlaser scheme, where ultracold alkaline-earth metal atoms, i.e., gain medium, are tightly confined in a two-color evanescent lattice that is in the ring shape and formed around a microsphere. To suppress the influence of the lattice-induced ac Stark shift on the moderately-narrow-linewidth laser transition, the red-detuned trapping beams operate at a magic wavelength while the wavelength of the blue-detuned trapping beam is set close to the other magic wavelength. The tiny mode volume and high quality factor of the microsphere ensure the strong atom-microcavity coupling in the bad-cavity regime. As a result, both saturation photon and critical atom numbers, which characterize the laser performance, are substantially reduced below unity. We explore the lasing action of the coupled system by using the Monte Carlo approach. Our scheme may be potentially generalized to the microlasers based on the forbidden clock transitions, holding the prospect for microscale active optical clocks in precision measurement and frequency metrology.

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Bao, Yicheng, Scarlett Seejia Yu, Loic Anderegg, Sean Burchesky, Derick Gonzalez-Acevedo, Eunmi Chae, Wolfgang Ketterle, Kang-Kuen Ni et John M. Doyle. « Fast optical transport of ultracold molecules over long distances ». New Journal of Physics, 7 septembre 2022. http://dx.doi.org/10.1088/1367-2630/ac900f.

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Abstract Optically trapped laser-cooled polar molecules hold promise for new science and technology in quantum information and quantum simulation. Large numerical aperture optical access and long trap lifetimes are needed for many studies, but these requirements are challenging to achieve in a magneto-optical trap (MOT) vacuum chamber that is connected to a cryogenic buffer gas beam source, as is the case for all molecule laser cooling experiments so far. Long distance transport of molecules greatly eases fulfilling these requirements as molecules are placed into a region separate from the MOT chamber. We realize a fast transport method for ultracold molecules based on an electronically focus-tunable lens combined with an optical lattice. The high transport speed is achieved by the 1D red-detuned optical lattice, which is generated by interference of a focus-tunable laser beam and a focus-fixed laser beam. Efficiency of 48(8)% is realized in the transport of ultracold calcium monofluoride (CaF) molecules over 46 cm distance in 50 ms, with a moderate heating from 32(2) μK to 53(4) μK. Positional stability of the molecular cloud allows for stable loading of an optical tweezer array with single molecules.

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Piilo, J., et K. A. Suominen. « Optical shielding of cold collisions in blue-detuned near-resonant optical lattices ». Physical Review A 66, n^o 1 (1 juillet 2002). http://dx.doi.org/10.1103/physreva.66.013401.

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Bozorgzadeh, Forough, Masoud Yousefi et Mohsen Akbari. « Optical forces on neutral atoms in the presence of fluctuating laser fields : Numerical analysis ». Communications in Theoretical Physics, 1 novembre 2022. http://dx.doi.org/10.1088/1572-9494/ac9f09.

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Abstract Doppler cooling of 88Rb atoms is studied in the presence of off-resonant red-detuned fluctuating laser fields. Using a semi-classical approach, we show that the relevant physical quantities in the cooling process, such as optical forces, damping coefficient, Doppler temperature, and atom number in the trap, are strongly affected by the laser amplitude and phase fluctuations. We found that the Doppler cooling limit is higher than the predicted Doppler theory for non-fluctuating lasers. This implies an additional heating mechanism exists due to the laser fluctuations. Furthermore, our numerical analysis shows that the effect of laser power stability on reducing the number of trapped atoms in an MOT is more substantial than the effect of laser linewidth.

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Chen, Hao, NingNing Yang, Chengzhi Qin, Wenwan Li, Bing Wang, Tianwen Han, Chi Zhang et al. « Real-time observation of frequency Bloch oscillations with fibre loop modulation ». Light : Science & ; Applications 10, n^o 1 (5 mars 2021). http://dx.doi.org/10.1038/s41377-021-00494-w.

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AbstractBloch oscillations (BOs) were initially predicted for electrons in a solid lattice to which a static electric field is applied. The observation of BOs in solids remains challenging due to the collision scattering and barrier tunnelling of electrons. Nevertheless, analogies of electron BOs for photons, acoustic phonons and cold atoms have been experimentally demonstrated in various lattice systems. Recently, BOs in the frequency dimension have been proposed and studied by using an optical micro-resonator, which provides a unique approach to controlling the light frequency. However, the finite resonator lifetime and intrinsic loss hinder the effect from being observed practically. Here, we experimentally demonstrate BOs in a synthetic frequency lattice by employing a fibre-loop circuit with detuned phase modulation. We show that a detuning between the modulation period and the fibre-loop roundtrip time acts as an effective vector potential and hence a constant effective force that can yield BOs in the modulation-induced frequency lattices. With a dispersive Fourier transformation, the pulse spectrum can be mapped into the time dimension, and its transient evolution can be precisely measured. This study offers a promising approach to realising BOs in synthetic dimensions and may find applications in frequency manipulations in optical fibre communication systems.

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Fan, Zhi-Yuan, Hang Qian et Jie Li. « Stationary optomagnonic entanglement and magnon-to-optics quantum state transfer via opto-magnomechanics ». Quantum Science and Technology, 17 novembre 2022. http://dx.doi.org/10.1088/2058-9565/aca3cf.

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Abstract We show how to prepare a steady-state entangled state between magnons and optical photons in an opto-magnomechanical configuration, where a mechanical vibration mode couples to a magnon mode in a ferrimagnet by the dispersive magnetostrictive interaction, and to an optical cavity by the radiation pressure. We find that, by appropriately driving the magnon mode and the cavity to simultaneously activate the magnomechanical Stokes and the optomechanical anti-Stokes scattering, a stationary optomagnonic entangled state can be created. We further show that, by activating the magnomechanical state-swap interaction and subsequently sending a weak red-detuned optical pulse to drive the cavity, the magnonic state can be read out in the cavity output field of the pulse via the mechanical transduction. The demonstrated entanglement and state-readout protocols in such a novel opto-magnomechanical configuration allow us to optically control, prepare, and read out quantum states of collective spin excitations in solids, and provide promising opportunities for the study of quantum magnonics, macroscopic quantum states, and magnonic quantum information processing.

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Voloshin, Andrey S., Nikita M. Kondratiev, Grigory V. Lihachev, Junqiu Liu, Valery E. Lobanov, Nikita Yu Dmitriev, Wenle Weng, Tobias J. Kippenberg et Igor A. Bilenko. « Dynamics of soliton self-injection locking in optical microresonators ». Nature Communications 12, n^o 1 (11 janvier 2021). http://dx.doi.org/10.1038/s41467-020-20196-y.

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AbstractSoliton microcombs constitute chip-scale optical frequency combs, and have the potential to impact a myriad of applications from frequency synthesis and telecommunications to astronomy. The demonstration of soliton formation via self-injection locking of the pump laser to the microresonator has significantly relaxed the requirement on the external driving lasers. Yet to date, the nonlinear dynamics of this process has not been fully understood. Here, we develop an original theoretical model of the laser self-injection locking to a nonlinear microresonator, i.e., nonlinear self-injection locking, and construct state-of-the-art hybrid integrated soliton microcombs with electronically detectable repetition rate of 30 GHz and 35 GHz, consisting of a DFB laser butt-coupled to a silicon nitride microresonator chip. We reveal that the microresonator’s Kerr nonlinearity significantly modifies the laser diode behavior and the locking dynamics, forcing laser emission frequency to be red-detuned. A novel technique to study the soliton formation dynamics as well as the repetition rate evolution in real-time uncover non-trivial features of the soliton self-injection locking, including soliton generation at both directions of the diode current sweep. Our findings provide the guidelines to build electrically driven integrated microcomb devices that employ full control of the rich dynamics of laser self-injection locking, key for future deployment of microcombs for system applications.

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Pryamikov, Andrey, Ljupco Hadzievski, Mikhail Fedoruk, Sergei Turitsyn et Alejandro Aceves. « Optical vortices in waveguides with discrete and continuous rotational symmetry ». Journal of the European Optical Society-Rapid Publications 17, n^o 1 (16 novembre 2021). http://dx.doi.org/10.1186/s41476-021-00168-5.

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AbstractCoherent vortex structures are fascinating physical objects that are widespread in nature: from large scale atmospheric phenomena, such as tornadoes and the Great Red Spot of Jupiter to microscopic size topological defects in quantum physics and optics. Unlike classical vortex dynamics in fluids, optical vortices feature new interesting properties. For instance, novel discrete optical vortices can be generated in photonic lattices, leading to new physics. In nonlinear optical media, vortices can be treated as solitons with nontrivial characteristics currently studied under the emerging field of topological photonics. Parallel to theoretical advances, new areas of the engineering applications based on light vortices have emerged. Examples include the possibility of carrying information coded in the vortex orbital angular momentum, understood as a spatial-division-multiplexing scheme, to the creation of optical tweezers for efficient manipulation of small objects. This report presents an overview highlighting some of the recent advances in the field of optical vortices with special attention on discrete vortex systems and related numerical methods for modeling propagation in multi-core fibers.

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