Counter beam lighting was introduced as well as transverse symmetrical lighting and longitudinal symmetrical lighting.Simulation experiments were carried out by using DIAlux lighting software for the above three light...Counter beam lighting was introduced as well as transverse symmetrical lighting and longitudinal symmetrical lighting.Simulation experiments were carried out by using DIAlux lighting software for the above three lighting methods.The results show that counter beam lighting is more reasonable to be adopted in the tunnel entrance zone because its threshold increment of disability glare is greater.Counter beam lighting can improve the background luminance of the obstacles and lighting efficiency compared with transverse symmetrical lighting and longitudinal symmetrical lighting.Therefore,tunnel lighting energy-saving can be achieved by reducing the road luminance demands and luminaries power.Longitudinal symmetrical lighting is conducive to the large luminaries spacing in the tunnel internal zone;so power consumption can be reduced by decreasing the number of luminaries used.Tunnel walls are unsuitable to pave with smooth or bright material.Installation height of the luminaries has less effect on counter beam lighting.展开更多
Conventionally,the spatially structured light beams produced by metasurfaces primarily highlight the polarization modulation of the beams propagating along the optical axis or the beams'spatial transmission trajec...Conventionally,the spatially structured light beams produced by metasurfaces primarily highlight the polarization modulation of the beams propagating along the optical axis or the beams'spatial transmission trajectory.In particular,along the optical axis,the polarization state is either constant or varies continuously in each output plane.Here,we develop innovative spatially structured light beams with continually changing polarization along any arbitrary spatial transmission trajectories.With tri-layer metallic metasurfaces,the geometric characteristics of each layer structure can be adjusted to modulate the phase and polarization state of the incident terahertz(THz)wave.The beam will converge to the predefined trajectory along several paths to generate a Bessel-like beam with longitudinal polarization changes.We demonstrate the versatility of the approach by designing two THz-band structured light beams with varying polarization states along the spatial helical transmission trajectory.Continuous linear polarization changes and linear polarization to right circular polarization(RCP)and back to linear polarization changes are realized respectively.The experimental results are basically consistent with the simulated results.Our proposal for arbitrary trajectory structured light beams with longitudinally varying polarization offers a practical method for continuously regulating the characteristics of spatial structured light beams with non-axial transmission.This technique has potential uses in optical encryption,particle manipulation,and biomedical imaging.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
A concept of divergence angle of light beams(DALB)is proposed to analyze the depth of field(DOF)of a 3D light-field display system.The mathematical model between DOF and DALB is established,and the conclusion that DOF...A concept of divergence angle of light beams(DALB)is proposed to analyze the depth of field(DOF)of a 3D light-field display system.The mathematical model between DOF and DALB is established,and the conclusion that DOF and DALB are inversely proportional is drawn.To reduce DALB and generate clear depth perception,a triple composite aspheric lens structure with a viewing angle of 100°is designed and experimentally demonstrated.The DALB-constrained 3D light-field display system significantly improves the clarity of 3D images and also performs well in imaging at a 3D scene with a DOF over 30 cm.展开更多
基金Funded by Key Laboratory of Ministry of Education for Conveyance and Equipment,East China Jiaotong University(No. 09JD09)
文摘Counter beam lighting was introduced as well as transverse symmetrical lighting and longitudinal symmetrical lighting.Simulation experiments were carried out by using DIAlux lighting software for the above three lighting methods.The results show that counter beam lighting is more reasonable to be adopted in the tunnel entrance zone because its threshold increment of disability glare is greater.Counter beam lighting can improve the background luminance of the obstacles and lighting efficiency compared with transverse symmetrical lighting and longitudinal symmetrical lighting.Therefore,tunnel lighting energy-saving can be achieved by reducing the road luminance demands and luminaries power.Longitudinal symmetrical lighting is conducive to the large luminaries spacing in the tunnel internal zone;so power consumption can be reduced by decreasing the number of luminaries used.Tunnel walls are unsuitable to pave with smooth or bright material.Installation height of the luminaries has less effect on counter beam lighting.
基金supported by the National Natural Science Foundation of China(Grant Nos.12074094 and 121774271)the Sino-German Mobility Program of the Sino-German Center for Science Funding(Grant No.M-0225)the Capacity Building for Science&Technology Innovation-Fundamental Scientific Research Funds(Grant No.00820531120017).
文摘Conventionally,the spatially structured light beams produced by metasurfaces primarily highlight the polarization modulation of the beams propagating along the optical axis or the beams'spatial transmission trajectory.In particular,along the optical axis,the polarization state is either constant or varies continuously in each output plane.Here,we develop innovative spatially structured light beams with continually changing polarization along any arbitrary spatial transmission trajectories.With tri-layer metallic metasurfaces,the geometric characteristics of each layer structure can be adjusted to modulate the phase and polarization state of the incident terahertz(THz)wave.The beam will converge to the predefined trajectory along several paths to generate a Bessel-like beam with longitudinal polarization changes.We demonstrate the versatility of the approach by designing two THz-band structured light beams with varying polarization states along the spatial helical transmission trajectory.Continuous linear polarization changes and linear polarization to right circular polarization(RCP)and back to linear polarization changes are realized respectively.The experimental results are basically consistent with the simulated results.Our proposal for arbitrary trajectory structured light beams with longitudinally varying polarization offers a practical method for continuously regulating the characteristics of spatial structured light beams with non-axial transmission.This technique has potential uses in optical encryption,particle manipulation,and biomedical imaging.
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.
基金supported by the National Key Research and Development Program of China(No.2021YFB3600504)the National Natural Science Foundation of China(Nos.62175015 and 62075016)。
文摘A concept of divergence angle of light beams(DALB)is proposed to analyze the depth of field(DOF)of a 3D light-field display system.The mathematical model between DOF and DALB is established,and the conclusion that DOF and DALB are inversely proportional is drawn.To reduce DALB and generate clear depth perception,a triple composite aspheric lens structure with a viewing angle of 100°is designed and experimentally demonstrated.The DALB-constrained 3D light-field display system significantly improves the clarity of 3D images and also performs well in imaging at a 3D scene with a DOF over 30 cm.
