Lidar, a technology at the heart of autonomous driving and robotic mobility, performs 3D imaging ofa complex scene by measuring the time of flight of returning light pulses. Many technological challenges,including enh...Lidar, a technology at the heart of autonomous driving and robotic mobility, performs 3D imaging ofa complex scene by measuring the time of flight of returning light pulses. Many technological challenges,including enhancement of the observation field of view (FoV), acceleration of the imaging frame rate,improvement of the ambiguity range, reduction of fabrication cost, and component size, must besimultaneously addressed so that lidar technology reaches the performance needed to strongly impact theglobal market. We propose an innovative solution to address the problem of wide FoV and extendedunambiguous range using an acousto-optic modulator that rapidly scans a large-area metasurface deflector.We further exploit a multiplexing illumination technique traditionally deployed in the context of telecommu-nication theory to extend the ambiguity range and to drastically improve the signal-to-noise ratio of themeasured signal. Compacting our metasurface-scanning lidar system to chip-scale dimension would opennew and exciting perspectives, eventually relevant to the autonomous vehicles and robotic industries.展开更多
Vortex beams with fractional topological charge(FTC) have many special characteristics and novel applications.However, one of the obstacles for their application is the difficulty of precisely determining the FTC of f...Vortex beams with fractional topological charge(FTC) have many special characteristics and novel applications.However, one of the obstacles for their application is the difficulty of precisely determining the FTC of fractional vortex beams. We find that when a vortex beam with an FTC illuminates a dynamic angular double slit(ADS), the far-field interference patterns that include the information of the FTC of the beam at the angular bisector direction of the ADS vary periodically. Based on this property, a simple dynamic ADS device and data fitting method can be used to precisely measure the FTC of a vortex light beam with an error of less than 5%.展开更多
We explore the impact of pumping beams with different transverse intensity profiles on the performance of the spinexchange relaxation-free(SERF) atomic magnetometers(AMs). We conduct experiments comparing the traditio...We explore the impact of pumping beams with different transverse intensity profiles on the performance of the spinexchange relaxation-free(SERF) atomic magnetometers(AMs). We conduct experiments comparing the traditional Gaussian optically-pumped AM with that utilizing the flat-top optically-pumped(FTOP) method. Our findings reveal that the FTOP-based approach outperforms the conventional method, exhibiting a larger response, a narrower magnetic resonance linewidth, and a superior low-frequency noise performance. Specifically, the use of FTOP method leads to a 16% enhancement in average sensitivity within 1 Hz–30 Hz frequency range. Our research emphasizes the significance of achieving transverse polarization uniformity in AMs, providing insights for future optimization efforts and sensitivity improvements in miniaturized magnetometers.展开更多
The alkali-atom density measurement method based on light absorption is highly suitable for a spin-exchange relaxationfree(SERF)atomic magnetometer because of its high-precision measurement and complete nonmagnetic in...The alkali-atom density measurement method based on light absorption is highly suitable for a spin-exchange relaxationfree(SERF)atomic magnetometer because of its high-precision measurement and complete nonmagnetic interference.In this study,the optical rotation angle detection system based on polarization balance detection is utilized to realize the alkali-atom density real-time measurement without affecting magnetic field measurement.We discovered that there exists an optimal frequency detuning of the probe light,which offers the highest sensitivity in alkali-atom density measurement and the lowest susceptibility to temperature fluctuations in terms of the scale factor.In contrast to conventional light absorption measurements based on pump light,this method demonstrated a threefold improvement in alkali-atom density measurement sensitivity while remaining immune to ambient magnetic fields and incident light intensity fluctuations.Furthermore,we utilized this method to achieve closed-loop temperature control with an accuracy of 0.04℃.展开更多
基金financially supported by the European Research Council proof of concept (ERC POC) under the European Union’s Horizon 2020 research and innovation program (Project i-Li DAR, Grant No. 874986)the CNRS prématuration+2 种基金the UCA Innovation Program (2020 startup deep Tech)the French defense procurement agency under the ANR ASTRID Maturation program, grant agreement number ANR-18-ASMA-0006supported with a postdoctoral fellowship grant by the Bodossaki Foundation (Athens, Greece)
文摘Lidar, a technology at the heart of autonomous driving and robotic mobility, performs 3D imaging ofa complex scene by measuring the time of flight of returning light pulses. Many technological challenges,including enhancement of the observation field of view (FoV), acceleration of the imaging frame rate,improvement of the ambiguity range, reduction of fabrication cost, and component size, must besimultaneously addressed so that lidar technology reaches the performance needed to strongly impact theglobal market. We propose an innovative solution to address the problem of wide FoV and extendedunambiguous range using an acousto-optic modulator that rapidly scans a large-area metasurface deflector.We further exploit a multiplexing illumination technique traditionally deployed in the context of telecommu-nication theory to extend the ambiguity range and to drastically improve the signal-to-noise ratio of themeasured signal. Compacting our metasurface-scanning lidar system to chip-scale dimension would opennew and exciting perspectives, eventually relevant to the autonomous vehicles and robotic industries.
基金Fundamental Research Funds for the Central UniversitiesNational Natural Science Foundation of China(NSFC)(11374008,11374238,11374239,11534008)
文摘Vortex beams with fractional topological charge(FTC) have many special characteristics and novel applications.However, one of the obstacles for their application is the difficulty of precisely determining the FTC of fractional vortex beams. We find that when a vortex beam with an FTC illuminates a dynamic angular double slit(ADS), the far-field interference patterns that include the information of the FTC of the beam at the angular bisector direction of the ADS vary periodically. Based on this property, a simple dynamic ADS device and data fitting method can be used to precisely measure the FTC of a vortex light beam with an error of less than 5%.
基金Project supported by the National Natural Science Foundation of China (Grant No. 62303029)the China Postdoctoral Science Foundation (Grant No. 2022M720364)the Innovation Program for Quantum Science and Technology (Grant Nos. 2021ZD0300500 and 2021ZD0300503)。
文摘We explore the impact of pumping beams with different transverse intensity profiles on the performance of the spinexchange relaxation-free(SERF) atomic magnetometers(AMs). We conduct experiments comparing the traditional Gaussian optically-pumped AM with that utilizing the flat-top optically-pumped(FTOP) method. Our findings reveal that the FTOP-based approach outperforms the conventional method, exhibiting a larger response, a narrower magnetic resonance linewidth, and a superior low-frequency noise performance. Specifically, the use of FTOP method leads to a 16% enhancement in average sensitivity within 1 Hz–30 Hz frequency range. Our research emphasizes the significance of achieving transverse polarization uniformity in AMs, providing insights for future optimization efforts and sensitivity improvements in miniaturized magnetometers.
文摘The alkali-atom density measurement method based on light absorption is highly suitable for a spin-exchange relaxationfree(SERF)atomic magnetometer because of its high-precision measurement and complete nonmagnetic interference.In this study,the optical rotation angle detection system based on polarization balance detection is utilized to realize the alkali-atom density real-time measurement without affecting magnetic field measurement.We discovered that there exists an optimal frequency detuning of the probe light,which offers the highest sensitivity in alkali-atom density measurement and the lowest susceptibility to temperature fluctuations in terms of the scale factor.In contrast to conventional light absorption measurements based on pump light,this method demonstrated a threefold improvement in alkali-atom density measurement sensitivity while remaining immune to ambient magnetic fields and incident light intensity fluctuations.Furthermore,we utilized this method to achieve closed-loop temperature control with an accuracy of 0.04℃.
