We introduce a new class of the chirped Airy–Gaussian vortex electron plasma(CAiGVEP)wave which constitutes the exact and continuous transition modes between the chirped Airy vortex and the chirped Gaussian vortex el...We introduce a new class of the chirped Airy–Gaussian vortex electron plasma(CAiGVEP)wave which constitutes the exact and continuous transition modes between the chirped Airy vortex and the chirped Gaussian vortex electron plasma wave.The intensity,the phase,and the angular momentum density flow of the CAiGVEP wave are discussed under different distribution factors and different chirp modes.展开更多
The nonparaxial propagation of radially polarized chirped Airy beams(RPCAiBs) in uniaxial crystal orthogonal to the optical axis is analytically studied. The effects of the first and the second order chirp factors, an...The nonparaxial propagation of radially polarized chirped Airy beams(RPCAiBs) in uniaxial crystal orthogonal to the optical axis is analytically studied. The effects of the first and the second order chirp factors, and the ratio of the extraordinary refractive index to the ordinary refractive index on the nonparaxial evolution of RPCAi Bs in different observation planes are investigated in detail. The results show that when one parameter changes, different components behave differently, and even the same component has various behavior in different directions. The initial slope of RPCAi Bs in the x-direction varies more with the first order chirp factor than that in the y-direction. Meanwhile, with the second order chirp factor becoming larger, the depth of the focus of the y-component in the x-direction decreases while that in the y-direction has no difference. In addition, the different ratios of the extraordinary refractive index to the ordinary refractive index change the difference of the depth of the focus between the x-and the y-components.展开更多
Light detection and ranging(LiDAR),as a hot imaging technology in both industry and academia,has undergone rapid innovation and evolution.The current mainstream direction is towards system miniaturization and integrat...Light detection and ranging(LiDAR),as a hot imaging technology in both industry and academia,has undergone rapid innovation and evolution.The current mainstream direction is towards system miniaturization and integration.There are many metrics that can be used to evaluate the performance of a LiDAR system,such as lateral resolution,ranging accuracy,stability,size,and price.Until recently,with the continuous enrichment of LiDAR application scenarios,the pursuit of imaging speed has attracted tremendous research interest.Particularly,for autonomous vehicles running on motorways or industrial automation applications,the imaging speed of LiDAR systems is a critical bottleneck.In this review,we will focus on discussing the upper speed limit of the LiDAR system.Based on the working mechanism,the limitation of optical parts on the maximum imaging speed is analyzed.The beam scanner has the greatest impact on imaging speed.We provide the working principle of current popular beam scanners used in LiDAR systems and summarize the main constraints on the scanning speed.Especially,we highlight the spectral scanning LiDAR as a new paradigm of ultrafast LiDAR.Additionally,to further improve the imaging speed,we then review the parallel detection methods,which include multiple-detector schemes and multiplexing technologies.Furthermore,we summarize the LiDAR systems with the fastest point acquisition rate reported nowadays.In the outlook,we address the current technical challenges for ultrafast LiDAR systems from different aspects and give a brief analysis of the feasibility of different approaches.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11775083 and 11374108)the Science and Technology Program of Guangzhou City(Grant No.2019050001)the Special Funds for the Cultivation of Guangdong College Students’Scientific and Technological Innovation(Grant Nos.pdjh2020a0149 and pdjh2019a0127).
文摘We introduce a new class of the chirped Airy–Gaussian vortex electron plasma(CAiGVEP)wave which constitutes the exact and continuous transition modes between the chirped Airy vortex and the chirped Gaussian vortex electron plasma wave.The intensity,the phase,and the angular momentum density flow of the CAiGVEP wave are discussed under different distribution factors and different chirp modes.
基金Projected supported by the National Natural Science Foundation of China(Grant Nos.11775083 and 11374108)the Science and Technology Program of Guangzhou Province,China(Grant No.2019050001)the Special Funds for the Cultivation of Guangdong College Students’Scientific and Technological Innovation,China(Grant No.pdjh2020a0149)。
文摘The nonparaxial propagation of radially polarized chirped Airy beams(RPCAiBs) in uniaxial crystal orthogonal to the optical axis is analytically studied. The effects of the first and the second order chirp factors, and the ratio of the extraordinary refractive index to the ordinary refractive index on the nonparaxial evolution of RPCAi Bs in different observation planes are investigated in detail. The results show that when one parameter changes, different components behave differently, and even the same component has various behavior in different directions. The initial slope of RPCAi Bs in the x-direction varies more with the first order chirp factor than that in the y-direction. Meanwhile, with the second order chirp factor becoming larger, the depth of the focus of the y-component in the x-direction decreases while that in the y-direction has no difference. In addition, the different ratios of the extraordinary refractive index to the ordinary refractive index change the difference of the depth of the focus between the x-and the y-components.
基金Tsinghua Shenzhen International Graduate School-Shenzhen Pengrui Young Faculty Program of Shenzhen Pengrui Foundation(SZPR2023008)Shenzhen Technology and Innovation Council(WDZC20200820160650001)。
文摘Light detection and ranging(LiDAR),as a hot imaging technology in both industry and academia,has undergone rapid innovation and evolution.The current mainstream direction is towards system miniaturization and integration.There are many metrics that can be used to evaluate the performance of a LiDAR system,such as lateral resolution,ranging accuracy,stability,size,and price.Until recently,with the continuous enrichment of LiDAR application scenarios,the pursuit of imaging speed has attracted tremendous research interest.Particularly,for autonomous vehicles running on motorways or industrial automation applications,the imaging speed of LiDAR systems is a critical bottleneck.In this review,we will focus on discussing the upper speed limit of the LiDAR system.Based on the working mechanism,the limitation of optical parts on the maximum imaging speed is analyzed.The beam scanner has the greatest impact on imaging speed.We provide the working principle of current popular beam scanners used in LiDAR systems and summarize the main constraints on the scanning speed.Especially,we highlight the spectral scanning LiDAR as a new paradigm of ultrafast LiDAR.Additionally,to further improve the imaging speed,we then review the parallel detection methods,which include multiple-detector schemes and multiplexing technologies.Furthermore,we summarize the LiDAR systems with the fastest point acquisition rate reported nowadays.In the outlook,we address the current technical challenges for ultrafast LiDAR systems from different aspects and give a brief analysis of the feasibility of different approaches.
