Recent progress in direct photodetection of light orbital angular momentum(OAM)based on the orbital photogalvanic effect(OPGE)provides an effective way for on-chip direct electric readout of orbital angular momentum,a...Recent progress in direct photodetection of light orbital angular momentum(OAM)based on the orbital photogalvanic effect(OPGE)provides an effective way for on-chip direct electric readout of orbital angular momentum,as well as large-scale integration focal-plane array devices.However,the recognition of OAM order from photocurrent response requires the extraction of circular polarization-dependent response.To date,the operation speed of such a detector is currently at the minute level and is limited by slow mechanical polarization modulation and low OAM recognition capability.We demonstrate that the operation speed can be greatly improved via an electrical polarization modulation strategy with a photoelastic modulator(PEM)accompanied by a phase-locked readout approach with a lock-in amplifier.We demonstrate an operation speed of up to kilohertz level with this new technology in the mid-infrared region(4μm)on an OAM detector using multilayer graphene as photosensitive material.In principle,with a new modulation and readout scheme,we can potentially increase the operation speed to megahertz with a PEM that operates at a state-ofthe-art speed.Our work paves the way toward high-speed operation of direct OAM detection devices based on the OPGE effect and pushes such technology to a more practical stage for focal plane array applications.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.62250065,62325401,12404389,12034001,12034003,and 62227822)the National Key Research and Development Program of China(Grant Nos.2021YFA1400100 and 2020YFA0308800)+1 种基金the Natural Science Basic Research Program of Shaanxi(Grant No.2024JC-YBQN-0063)the Open Fund of the State Key Laboratory of Infra-red Physics(Grant No.SITP-NLIST-ZD-2023-02)。
文摘Recent progress in direct photodetection of light orbital angular momentum(OAM)based on the orbital photogalvanic effect(OPGE)provides an effective way for on-chip direct electric readout of orbital angular momentum,as well as large-scale integration focal-plane array devices.However,the recognition of OAM order from photocurrent response requires the extraction of circular polarization-dependent response.To date,the operation speed of such a detector is currently at the minute level and is limited by slow mechanical polarization modulation and low OAM recognition capability.We demonstrate that the operation speed can be greatly improved via an electrical polarization modulation strategy with a photoelastic modulator(PEM)accompanied by a phase-locked readout approach with a lock-in amplifier.We demonstrate an operation speed of up to kilohertz level with this new technology in the mid-infrared region(4μm)on an OAM detector using multilayer graphene as photosensitive material.In principle,with a new modulation and readout scheme,we can potentially increase the operation speed to megahertz with a PEM that operates at a state-ofthe-art speed.Our work paves the way toward high-speed operation of direct OAM detection devices based on the OPGE effect and pushes such technology to a more practical stage for focal plane array applications.
