Pub Date : 2023-08-31DOI: 10.3788/COL202321.010005
Jihua Zhang, Jinyong Ma, D. Neshev, A. Sukhorukov
Two-photon state with spatial entanglement is an essential resource for testing fundamental laws of quantum mechanics and various quantum applications. Its creation typically relies on spontaneous parametric down-conversion in bulky nonlinear crystals where the tunability of spatial entanglement is limited. Here, we predict that ultrathin nonlinear lithium niobate metasurfaces can generate and diversely tune spatially entangled photon pairs. The spatial properties of photons including the emission pattern, rate, and degree of spatial entanglement are analysed theoretically with the coupled mode theory and Schmidt decomposition method. We show that by leveraging the strong angular dispersion of the metasurface, the degree of spatial entanglement quantified by the Schmidt number can be decreased or increased by changing the pump laser wavelength and a Gaussian beam size. This flexibility can facilitate diverse quantum applications of entangled photon states generated from nonlinear metasurfaces.
{"title":"Photon pair generation from lithium niobate metasurface with tunable spatial entanglement","authors":"Jihua Zhang, Jinyong Ma, D. Neshev, A. Sukhorukov","doi":"10.3788/COL202321.010005","DOIUrl":"https://doi.org/10.3788/COL202321.010005","url":null,"abstract":"Two-photon state with spatial entanglement is an essential resource for testing fundamental laws of quantum mechanics and various quantum applications. Its creation typically relies on spontaneous parametric down-conversion in bulky nonlinear crystals where the tunability of spatial entanglement is limited. Here, we predict that ultrathin nonlinear lithium niobate metasurfaces can generate and diversely tune spatially entangled photon pairs. The spatial properties of photons including the emission pattern, rate, and degree of spatial entanglement are analysed theoretically with the coupled mode theory and Schmidt decomposition method. We show that by leveraging the strong angular dispersion of the metasurface, the degree of spatial entanglement quantified by the Schmidt number can be decreased or increased by changing the pump laser wavelength and a Gaussian beam size. This flexibility can facilitate diverse quantum applications of entangled photon states generated from nonlinear metasurfaces.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"58 2 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90937055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-27DOI: 10.3788/col202321.092701
Wei-Hang Zhang, Ying-hao Ye, Lei Zeng, Enze Li, Jing-Yuan Peng, D. Ding, B. Shi
One of the major difficulties in realizing a high-dimensional frequency converter for conventional optical vortex (COV) stems from the difference in ring diameter of COV modes with different topological charge numbers l. Here, we implement a high-dimensional frequency convertor for perfect optical vortex (POV) modes with invariant size through the four-wave mixing (FWM) process by utilizing Bessel-Gaussian beams instead of Laguerre-Gaussian beams. The measured conversion efficiency from 1530 nm to 795 nm is independent of l at least in subspace of {-6,...,6}, and the achieved conversion fidelities for two-dimensional (2D) superposed POV states exceed 97%. We further realize the frequency conversion of 3D, 5D and 7D superposition states with fidelities as high as 96.70%, 89.16% and 88.68%, respectively. The reported scheme is implemented in hot atomic vapor, it's also compatible with the cold atomic system and may find applications in high-capacity and long-distance quantum communication.
{"title":"High-dimensional frequency conversion in a hot atomic system","authors":"Wei-Hang Zhang, Ying-hao Ye, Lei Zeng, Enze Li, Jing-Yuan Peng, D. Ding, B. Shi","doi":"10.3788/col202321.092701","DOIUrl":"https://doi.org/10.3788/col202321.092701","url":null,"abstract":"One of the major difficulties in realizing a high-dimensional frequency converter for conventional optical vortex (COV) stems from the difference in ring diameter of COV modes with different topological charge numbers l. Here, we implement a high-dimensional frequency convertor for perfect optical vortex (POV) modes with invariant size through the four-wave mixing (FWM) process by utilizing Bessel-Gaussian beams instead of Laguerre-Gaussian beams. The measured conversion efficiency from 1530 nm to 795 nm is independent of l at least in subspace of {-6,...,6}, and the achieved conversion fidelities for two-dimensional (2D) superposed POV states exceed 97%. We further realize the frequency conversion of 3D, 5D and 7D superposition states with fidelities as high as 96.70%, 89.16% and 88.68%, respectively. The reported scheme is implemented in hot atomic vapor, it's also compatible with the cold atomic system and may find applications in high-capacity and long-distance quantum communication.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"41 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84942117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Shack – Hartmann wavefront sensor (SHWFS) is commonly used for its high speed and precision in adaptive optics. However, its performance is limited in low light conditions, particularly when observing faint objects in astronomical applications. Instead of a pixelated detector, we present a new approach for wavefront sensing using a single-pixel detector, which is able to code the spatial position of a light spot array into the polarization dimension and decode the polarization state in the polar coordinate. We propose validation experiments with simple and complex wavefront distortions to demonstrate our approach as a promising alternative to traditional SHWFS systems, with potential applications in a wide range of fields.
{"title":"Single-pixel wavefront sensing via vectorial polarization modulation","authors":"æ¦ç”· æ�Ž, 毓 曹, 禹 å®�, 锋æ�° ä¹, å…¨ å™, 晓军 许","doi":"10.3788/col202321.090008","DOIUrl":"https://doi.org/10.3788/col202321.090008","url":null,"abstract":"The Shack – Hartmann wavefront sensor (SHWFS) is commonly used for its high speed and precision in adaptive optics. However, its performance is limited in low light conditions, particularly when observing faint objects in astronomical applications. Instead of a pixelated detector, we present a new approach for wavefront sensing using a single-pixel detector, which is able to code the spatial position of a light spot array into the polarization dimension and decode the polarization state in the polar coordinate. We propose validation experiments with simple and complex wavefront distortions to demonstrate our approach as a promising alternative to traditional SHWFS systems, with potential applications in a wide range of fields.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135600377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Terahertz (THz) lenses have numerous applications in imaging and communication systems. Currently, the common THz lenses are still based on the traditional design of a circular convex lens. In this work, we present a method for the design of a 3D-printed multilevel THz lens, taking advantage of the benefits offered by 3D printing technology, including compact size, lightweight construction, and cost-effectiveness. The approach utilizes an inverse design methodology, employing optimization methods to promise accurate performance. To reduce simulation time, we employ the finite-difference time-domain method in cylindrical coordinates for near-field computation and couple it with the Rayleigh–Sommerfeld diffraction theory to address far-field calculations. This technology holds great potential for various applications in the field of THz imaging, sensing, and communications, offering a novel approach to the design and development of functional devices operating in the THz frequency range.
{"title":"Inverse design on terahertz multilevel diffractive lens based on 3D printing","authors":"Chenyu Shi, Yu Wang, Qiongjun Liu, Sai Chen, Weipeng Zhao, Xiaojun Wu, Jierong Cheng, Shengjiang Chang","doi":"10.3788/col202321.110006","DOIUrl":"https://doi.org/10.3788/col202321.110006","url":null,"abstract":"Terahertz (THz) lenses have numerous applications in imaging and communication systems. Currently, the common THz lenses are still based on the traditional design of a circular convex lens. In this work, we present a method for the design of a 3D-printed multilevel THz lens, taking advantage of the benefits offered by 3D printing technology, including compact size, lightweight construction, and cost-effectiveness. The approach utilizes an inverse design methodology, employing optimization methods to promise accurate performance. To reduce simulation time, we employ the finite-difference time-domain method in cylindrical coordinates for near-field computation and couple it with the Rayleigh–Sommerfeld diffraction theory to address far-field calculations. This technology holds great potential for various applications in the field of THz imaging, sensing, and communications, offering a novel approach to the design and development of functional devices operating in the THz frequency range.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135612376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3788/col202321.101203
Jiahui Zhang, Feng Xu, Ran An, Lin Wang, Min Jiang, Guanghui Wang, Yanqing Lu
Fluorescence detection is widely used in biology and medicine, while the realization of on-chip fluorescence detection is vital for the portable and point-of-care test (POCT) application. In this Letter, we propose an efficient fluorescence excitation and collection system using an integrated GaN chip consisting of a slot waveguide and a one-dimensional photonic crystal (1D PC) waveguide. The slot waveguide is used to confine the excitation light for intense light–sample interaction, and the one-trip collection efficiency at the end of slot waveguide is up to 14.65%. More interestingly, due to the introduction of the 1D PC waveguide, the fluorescence signal is directly filtered out, and the excitation light is reflected to the slot waveguide for multiple excitations. Its transmittances for the designed exciting wavelength of 520 nm and the fluorescent wavelength of 612 nm are 0.2% and 85.4%, respectively. Finally, based on numerical analysis, the total fluorescence collection efficiency in our system amounts to 15.93%. It is the first time, to our knowledge, that the concept of an all-in-one-chip fluorescence detection system has been proposed, which paves the way for on-chip fluorescence excitation and collection, and may find potential applications of miniaturized and portable devices for biomedical fluorescence detection.
{"title":"Integrated fluorescence excitation, collection, and filtering on a GaN waveguide chip","authors":"Jiahui Zhang, Feng Xu, Ran An, Lin Wang, Min Jiang, Guanghui Wang, Yanqing Lu","doi":"10.3788/col202321.101203","DOIUrl":"https://doi.org/10.3788/col202321.101203","url":null,"abstract":"Fluorescence detection is widely used in biology and medicine, while the realization of on-chip fluorescence detection is vital for the portable and point-of-care test (POCT) application. In this Letter, we propose an efficient fluorescence excitation and collection system using an integrated GaN chip consisting of a slot waveguide and a one-dimensional photonic crystal (1D PC) waveguide. The slot waveguide is used to confine the excitation light for intense light–sample interaction, and the one-trip collection efficiency at the end of slot waveguide is up to 14.65%. More interestingly, due to the introduction of the 1D PC waveguide, the fluorescence signal is directly filtered out, and the excitation light is reflected to the slot waveguide for multiple excitations. Its transmittances for the designed exciting wavelength of 520 nm and the fluorescent wavelength of 612 nm are 0.2% and 85.4%, respectively. Finally, based on numerical analysis, the total fluorescence collection efficiency in our system amounts to 15.93%. It is the first time, to our knowledge, that the concept of an all-in-one-chip fluorescence detection system has been proposed, which paves the way for on-chip fluorescence excitation and collection, and may find potential applications of miniaturized and portable devices for biomedical fluorescence detection.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136206809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3788/col202321.101601
Hanchi Xia, Tao Zhang, Yuehui Wang, Yaping Qi, Fan Zhang, Zhenping Wu, Yang Zhang
Flexible devices provide advantages such as conformability, portability, and low cost. Paper-based electronics offers a number of advantages for many applications. It is lightweight, inexpensive, and biodegradable, making it an ideal choice for disposable electronics. In this work, we propose a novel configuration of photodetectors using paper as flexible substrates and amorphous Ga2O3 as the active materials, respectively. The photoresponse characteristics are investigated systematically. A decent responsivity yield and a specific detectivity of up to 66 mA/W and 3×1012 Jones were obtained at a low operating voltage of 10 V. The experiments also demonstrate that neither the twisting nor bending deformation can bring obvious performance degradation to the device. This work presents a candidate strategy for the application of conventional paper substrates to low-cost flexible solar-blind photodetectors, showing the potential of being integrated with other materials to create interactive flexible circuits.
{"title":"Paper-based amorphous Ga2O3 solar-blind photodetector with improved flexibility and stability","authors":"Hanchi Xia, Tao Zhang, Yuehui Wang, Yaping Qi, Fan Zhang, Zhenping Wu, Yang Zhang","doi":"10.3788/col202321.101601","DOIUrl":"https://doi.org/10.3788/col202321.101601","url":null,"abstract":"Flexible devices provide advantages such as conformability, portability, and low cost. Paper-based electronics offers a number of advantages for many applications. It is lightweight, inexpensive, and biodegradable, making it an ideal choice for disposable electronics. In this work, we propose a novel configuration of photodetectors using paper as flexible substrates and amorphous Ga2O3 as the active materials, respectively. The photoresponse characteristics are investigated systematically. A decent responsivity yield and a specific detectivity of up to 66 mA/W and 3×1012 Jones were obtained at a low operating voltage of 10 V. The experiments also demonstrate that neither the twisting nor bending deformation can bring obvious performance degradation to the device. This work presents a candidate strategy for the application of conventional paper substrates to low-cost flexible solar-blind photodetectors, showing the potential of being integrated with other materials to create interactive flexible circuits.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136207199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We demonstrate a deep-learning neural network (DNN) method for the measurement of molecular alignment by using the molecular-alignment-based cross-correlation polarization-gating frequency resolved optical gating (M-XFROG) technique. Our network has the capacity for direct measurement of molecular alignment from the FROG traces. In a proof-of-principle experiment, we have demonstrated our method in O2 molecules. With our method, the molecular alignment factor ⟨cos2 θ⟩(t) of O2, impulsively excited by a pump pulse, was directly reconstructed. The accuracy and validity of the reconstruction have been verified by comparison with the simulations based on experimental parameters.
{"title":"Measurement of molecular alignment with deep learning-based M-XFROG technique","authors":"Wanchen Tao, Siqi Sun, Lixin He, Yanqing He, Jianchang Hu, Yu Deng, Chengqing Xu, Pengfei Lan, Peixiang Lu","doi":"10.3788/col202321.120021","DOIUrl":"https://doi.org/10.3788/col202321.120021","url":null,"abstract":"We demonstrate a deep-learning neural network (DNN) method for the measurement of molecular alignment by using the molecular-alignment-based cross-correlation polarization-gating frequency resolved optical gating (M-XFROG) technique. Our network has the capacity for direct measurement of molecular alignment from the FROG traces. In a proof-of-principle experiment, we have demonstrated our method in O2 molecules. With our method, the molecular alignment factor ⟨cos2 θ⟩(t) of O2, impulsively excited by a pump pulse, was directly reconstructed. The accuracy and validity of the reconstruction have been verified by comparison with the simulations based on experimental parameters.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136259385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this Letter, we proposed and experimentally demonstrated a directly modulated tunable laser based on the multi-wave-length distributed feedback (DFB) laser array. The lasers are placed in series to avoid the usage of an optical combiner and additional power loss. A three-section design is utilized to reduce the interference from other lasers and improve the electro-optic response bandwidth. Besides, the reconstruction-equivalent-chirp technique is used to simplify the grating fabrication and precisely control the grating phase. We realized 12 channels with 100 GHz spacing with high side mode suppression ratios of above 50 dB. The output power of all the channels is above 14 mW. The 3 dB electro-optic bandwidth is above 20 GHz at a bias current of 100 mA for all four lasers. A 25 Gb/s data transmission over a standard single-mode fiber of up to 10 km is demonstrated for all 12 channels, and 50 Gb/s data per wavelength is obtained through the four-level pulse amplitude modulation. The proposed directly modulated tunable in-series DFB laser array shows the potential for a compact and low-cost light source for wavelength division multiplexing (WDM) systems, such as next-generation front-haul networks and passive optical networks.
{"title":"Directly modulated 25 Gbaud/s tunable in-series DFB laser array for WDM systems","authors":"Zhenxing Sun, Yaguang Wang, Rulei Xiao, Leilei Wang, Yangyang Gong, Y. Chiu, Xiangfei Chen","doi":"10.3788/col202321.011403","DOIUrl":"https://doi.org/10.3788/col202321.011403","url":null,"abstract":"In this Letter, we proposed and experimentally demonstrated a directly modulated tunable laser based on the multi-wave-length distributed feedback (DFB) laser array. The lasers are placed in series to avoid the usage of an optical combiner and additional power loss. A three-section design is utilized to reduce the interference from other lasers and improve the electro-optic response bandwidth. Besides, the reconstruction-equivalent-chirp technique is used to simplify the grating fabrication and precisely control the grating phase. We realized 12 channels with 100 GHz spacing with high side mode suppression ratios of above 50 dB. The output power of all the channels is above 14 mW. The 3 dB electro-optic bandwidth is above 20 GHz at a bias current of 100 mA for all four lasers. A 25 Gb/s data transmission over a standard single-mode fiber of up to 10 km is demonstrated for all 12 channels, and 50 Gb/s data per wavelength is obtained through the four-level pulse amplitude modulation. The proposed directly modulated tunable in-series DFB laser array shows the potential for a compact and low-cost light source for wavelength division multiplexing (WDM) systems, such as next-generation front-haul networks and passive optical networks.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"289 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74395291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3788/col202321.103401
Haoxuan Si, Lianqiang Shan, Huiyao Du, Li Jiang, Shengzhen Yi, Weimin Zhou, Zhanshan Wang
Curved crystal imaging is an important means of plasma diagnosis. Due to the short wavelengths of high-energy X rays and the fixed lattice constant of the spherical crystal, it is difficult to apply the spherical crystal in high-energy X-ray imaging. In this study, we have developed a high-energy, high-resolution X-ray imager based on a toroidal crystal that can effectively correct astigmatism. We prepared a Ge 〈5 1 1〉 toroidal crystal for backlighting Mo Kα1 characteristic lines (∼17.48 keV) and verified its high-resolution imaging ability in high-energy X-ray region, achieving a spatial resolution of 5–10 µm in a field of view larger than 1.0 mm.
{"title":"High-resolution Mo Kα X-ray monochromatic backlight imaging using a toroidal crystal","authors":"Haoxuan Si, Lianqiang Shan, Huiyao Du, Li Jiang, Shengzhen Yi, Weimin Zhou, Zhanshan Wang","doi":"10.3788/col202321.103401","DOIUrl":"https://doi.org/10.3788/col202321.103401","url":null,"abstract":"Curved crystal imaging is an important means of plasma diagnosis. Due to the short wavelengths of high-energy X rays and the fixed lattice constant of the spherical crystal, it is difficult to apply the spherical crystal in high-energy X-ray imaging. In this study, we have developed a high-energy, high-resolution X-ray imager based on a toroidal crystal that can effectively correct astigmatism. We prepared a Ge 〈5 1 1〉 toroidal crystal for backlighting Mo Kα1 characteristic lines (∼17.48 keV) and verified its high-resolution imaging ability in high-energy X-ray region, achieving a spatial resolution of 5–10 µm in a field of view larger than 1.0 mm.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135181733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：