Metasurfaces composed of two-dimensional nanopillar arrays can manipulate light fields in desirable ways and exhibit the unique advantage of beam steering.Here,we experimentally demonstrate a metasurface-based wide-an...Metasurfaces composed of two-dimensional nanopillar arrays can manipulate light fields in desirable ways and exhibit the unique advantage of beam steering.Here,we experimentally demonstrate a metasurface-based wide-angle broadband all-dielectric blazed grating with an extreme incident angle of up to 80°,which is achieved by optimizing the wide-angle phase shifts and transmissivities of the unit cells.It exhibits a maximum diffraction efficiency of 72%and a high average efficiency of 64%over a wide range of incident angles from−80° to 45° at 1.55μm.Moreover,the proposed grating has a broad bandwidth of 200 nm(1.45-1.65μm),and average efficiencies of more than 50%can be achieved experimentally over the same incidence angles.Our results may pave the way for the creation of novel and efficient flat optical devices for wavefront control.展开更多
A novel grating coupler with a stair-step blaze profile is proposed. The coupler is a CMOS process compatible device and can be used for light coupling in optical communication. The blaze profile can be optimized to o...A novel grating coupler with a stair-step blaze profile is proposed. The coupler is a CMOS process compatible device and can be used for light coupling in optical communication. The blaze profile can be optimized to obtain a high efficiency of 66.7% for the out-of-plane coupling at the centre wavelength of 1595 nm with a 1 dB bandwidth of 41 nm. Five key parameters of the stair-step blaze grating and their effects on the coupling are discussed for the application in L band telecommunication.展开更多
Far-field intensity and diffraction efficiency of the blazed reflection gratings illuminated with broad-bandwidth and divergent beam are investigated.When the spectral width and divergence of the incident beam with a ...Far-field intensity and diffraction efficiency of the blazed reflection gratings illuminated with broad-bandwidth and divergent beam are investigated.When the spectral width and divergence of the incident beam with a constant energy increase,the maximum intensity decreases,and the half width at e-2 of the maximum intensity becomes wider.Diffraction efficiency has no deterioration for the blazed grating with a proper groove shape even when the incident light contains a broad range of wavelengths and comes from a wide range of angles.展开更多
Grating optics lie in the heart of X-ray spectroscopy instruments.The low efficiency and angular dispersion of conventional single-layer-coated gratings significantly limit the transmission and energy resolution of mo...Grating optics lie in the heart of X-ray spectroscopy instruments.The low efficiency and angular dispersion of conventional single-layer-coated gratings significantly limit the transmission and energy resolution of monochromators and spectrometers,particularly in the tender X-ray region(E=1-5 keV).Multilayer-coated blazed gratings(MLBGs)operating at high diffraction orders offer the advantage of achieving both high efficiency and high dispersion simultaneously.Tender X-ray monochromators and spectrometers using different high-order MLBGs have been designed,all demonstrating one to two orders of magnitude higher transmission compared to conventional systems.By employing a 2400 l/mm MLBG at the-4th or-8th diffraction order,the theoretical energy resolution of the instrument is improved by two to three times at 2.5 keV.Two MLBGs operating at the-2nd and-4th orders have been fabricated,showcasing remarkable efficiencies of 34%-12%at 2.5 keV,surpassing that of single-layer-coated gratings by an order of magnitude.Further optimization of manufacturing accuracy can yield even higher efficiencies.The measured angular dispersion agrees well with theoretical predictions,supporting the potential for high resolution.High-order MLBG optics pave the way for a new generation of tender X-ray monochromators/spectrometers that offer both high transmission and high resolution.展开更多
基金support by the Advanced Integrated Optoelectronics Facility at Tianjin University
文摘Metasurfaces composed of two-dimensional nanopillar arrays can manipulate light fields in desirable ways and exhibit the unique advantage of beam steering.Here,we experimentally demonstrate a metasurface-based wide-angle broadband all-dielectric blazed grating with an extreme incident angle of up to 80°,which is achieved by optimizing the wide-angle phase shifts and transmissivities of the unit cells.It exhibits a maximum diffraction efficiency of 72%and a high average efficiency of 64%over a wide range of incident angles from−80° to 45° at 1.55μm.Moreover,the proposed grating has a broad bandwidth of 200 nm(1.45-1.65μm),and average efficiencies of more than 50%can be achieved experimentally over the same incidence angles.Our results may pave the way for the creation of novel and efficient flat optical devices for wavefront control.
基金Project supported by the National Natural Science Foundation of China (Grant No.60877036)the National Basic Research Program of China (Grant Nos.2006CB302803 and 2011CB301701)+1 种基金the State Key Laboratory of Advanced Optical Communication Systems and Networks,China (Grant No.2008SH02)the Knowledge Innovation Program of Institute of Semiconductors,Chinese Academy of Sciences (Grant No.ISCAS2008T10)
文摘A novel grating coupler with a stair-step blaze profile is proposed. The coupler is a CMOS process compatible device and can be used for light coupling in optical communication. The blaze profile can be optimized to obtain a high efficiency of 66.7% for the out-of-plane coupling at the centre wavelength of 1595 nm with a 1 dB bandwidth of 41 nm. Five key parameters of the stair-step blaze grating and their effects on the coupling are discussed for the application in L band telecommunication.
基金Key Technologies R&D Programme of Hubei Province(2005AA101B10)
文摘Far-field intensity and diffraction efficiency of the blazed reflection gratings illuminated with broad-bandwidth and divergent beam are investigated.When the spectral width and divergence of the incident beam with a constant energy increase,the maximum intensity decreases,and the half width at e-2 of the maximum intensity becomes wider.Diffraction efficiency has no deterioration for the blazed grating with a proper groove shape even when the incident light contains a broad range of wavelengths and comes from a wide range of angles.
基金National Key Research and Development Program of China(2022YFA1603503)National Natural Science Foundation of China(12075170)。
文摘Grating optics lie in the heart of X-ray spectroscopy instruments.The low efficiency and angular dispersion of conventional single-layer-coated gratings significantly limit the transmission and energy resolution of monochromators and spectrometers,particularly in the tender X-ray region(E=1-5 keV).Multilayer-coated blazed gratings(MLBGs)operating at high diffraction orders offer the advantage of achieving both high efficiency and high dispersion simultaneously.Tender X-ray monochromators and spectrometers using different high-order MLBGs have been designed,all demonstrating one to two orders of magnitude higher transmission compared to conventional systems.By employing a 2400 l/mm MLBG at the-4th or-8th diffraction order,the theoretical energy resolution of the instrument is improved by two to three times at 2.5 keV.Two MLBGs operating at the-2nd and-4th orders have been fabricated,showcasing remarkable efficiencies of 34%-12%at 2.5 keV,surpassing that of single-layer-coated gratings by an order of magnitude.Further optimization of manufacturing accuracy can yield even higher efficiencies.The measured angular dispersion agrees well with theoretical predictions,supporting the potential for high resolution.High-order MLBG optics pave the way for a new generation of tender X-ray monochromators/spectrometers that offer both high transmission and high resolution.
