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
Based on the vector diffraction theory, a super-resolution longitudinally polarized optical needle with ultra-long depth of focus(DOF) is generated by tightly focusing a radially polarized beam that is modulated by a ...Based on the vector diffraction theory, a super-resolution longitudinally polarized optical needle with ultra-long depth of focus(DOF) is generated by tightly focusing a radially polarized beam that is modulated by a self-designed ternary hybrid(phase/amplitude) filter(THF). Both the phase and the amplitude patterns of THF are judiciously optimized by the versatile particle swarm optimization(PSO) searching algorithm. For the focusing configuration with a combination of a high numerical aperture(NA) and the optimized sine-shaped THFs, an optical needle with the full width at half maximum(FWHM) of 0.414λ and the DOF of 7.58λ is accessed, which corresponds to an aspect ratio of 18.3. The demonstrated longitudinally polarized super-resolution light needle with high aspect ratio opens up broad applications in high-density optical data storage, nano-photolithography, super-resolution imaging and high-efficiency particle trapping.展开更多
The brightest flashlight named Imalent MS32 is capable of outputting up to 200,000 lumens of light,more than any other commercially available flashlight.Imagine having the ability to turn night into day in the palm of...The brightest flashlight named Imalent MS32 is capable of outputting up to 200,000 lumens of light,more than any other commercially available flashlight.Imagine having the ability to turn night into day in the palm of yourself and you kind of get a sense of what using the world's brightest flashlight feels and looks like.The Imalent MS32 is so incredibly powerful that the only other flashlight you can even compare it to is the Imalent MS18,the previous holder of the title of“world's brightest flashlight”.And that one was virtually half as powerful as the MS32,with a peak brightness of just 100,000 lumens.The LED‑powered light beam of the MS32 can reach as far as 1,618 meters and is the equivalent of 100 car lights in terms of brightness.展开更多
Based on vectorial Debye theory, tight focusing of radially and azimuthally polarized vortex beams passing through a dielectric interface are studied. The intensity distribution in the focal region is illustrated by n...Based on vectorial Debye theory, tight focusing of radially and azimuthally polarized vortex beams passing through a dielectric interface are studied. The intensity distribution in the focal region is illustrated by numerical calculations. We show the influence of numerical-aperture （NA） on the full-width at half maximum （FWHM） of the focal spot or the focal hole. It has been found that compared with the azimuthally polarized Besse^Gaussian （BG） beams, the longitudinal component in the z direction of the radially polarized BG beams has no influence on the FWHM of the focal spot and hole, but enhances the total light intensity.展开更多
Static strength finite element analysis was conducted to decrease the weight of a skeleton vehicle＇s frame. Results indicated that the maximum stress occurs on the front beam ＇s variable section area. Dynamic sensit...Static strength finite element analysis was conducted to decrease the weight of a skeleton vehicle＇s frame. Results indicated that the maximum stress occurs on the front beam ＇s variable section area. Dynamic sensitivity analysis elucidated the relationship between the maximum stress and the thickness of a particular beam,e. g.,top,middle,and bottom beam. Displacement was analyzed by the key part that influenced the maximum stress. Finally,the new plan using BS960 super-high-strength beam steel and the preferred beam thickness was compared with the original plan. New combinations of beam thickness were introduced on the basis of different purposes; the maximum responding light w eight ratio was 21%.展开更多
Recently,structured light beams have attracted substantial attention in many applications,including optical communications,imaging,optical tweezers,and quantum optics.We propose and experimentally demonstrate a reconf...Recently,structured light beams have attracted substantial attention in many applications,including optical communications,imaging,optical tweezers,and quantum optics.We propose and experimentally demonstrate a reconfigurable structured light beam generator in order to generate diverse structured light beams with adjustable beam types,beam orders,and beam sizes.By controlling the sizes of generated free-space structured light beams,free-space orbital angular momentum(OAM)beams and vector beams are coupled into an air-core fiber.To verify that our structured light generator enables generating structured light with high beam quality,polarization distributions and mode purity of generated OAM beams and vector beams in both free space and air-core fiber are characterized.Such a structured light generator may pave the way for future applications based on higher-order structured light beams.展开更多
By using an amplitude-type spatial light modulator to load angular spectrum of Mathieu function distribution along a narrow annular pupils, the Durnin’s experimental setup is extended to generate various types of Mat...By using an amplitude-type spatial light modulator to load angular spectrum of Mathieu function distribution along a narrow annular pupils, the Durnin’s experimental setup is extended to generate various types of Mathieu beams. As a special type of Mathieu beams, Bessel beams are also generated using this optical setup. Furthermore, the optical morphology of the Mathieu beams family are also presented and analyzed.展开更多
It is shown that a Gaussian light beam transmitting through a planar thin dielectric slab in the air undergoes four different effects, i.e. lateral Goos-Hanchen-like （GHL） displacement, angular deflection, width mod...It is shown that a Gaussian light beam transmitting through a planar thin dielectric slab in the air undergoes four different effects, i.e. lateral Goos-Hanchen-like （GHL） displacement, angular deflection, width modification and longitudinal focal shift as compared with the results predicted by geometrical optics. According to the Taylor expansion of the exponent of transmission coefficient when expressed as an exponential form, the lateral GHL displacement and the angular deflection are the first-order effects and can be negative or positive. The width modification and the longitudinal focal shift are the second-order effects and can also be positive or negative. Owing to the waist-width dependent term, the non-geometrical effects of transmitted beam are not identical with the non-specular effects of reflected beam. The conditions for the validity of those effects are suggested and numerical simulations are also given.展开更多
This paper analytically investigates the interaction of light filaments generated by a femtosecond laser beam in air. It obtains the Hamiltonian of a total laser field and interaction force between two filaments with ...This paper analytically investigates the interaction of light filaments generated by a femtosecond laser beam in air. It obtains the Hamiltonian of a total laser field and interaction force between two filaments with different phase shifts and crossing angles. The property of the interaction force, which leads the attraction or repulsion of filaments, is basically dependent on the phase shift between filaments. The crossing angle between two filaments can only determine the magnitude of the interaction force, but does not change the property of the force.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 Natural Science Foundation of China(Nos.61575139,61605136,51602213 and 11604236)the Youth Foundation of the Taiyuan University of Technology(No.2015QN066)
文摘Based on the vector diffraction theory, a super-resolution longitudinally polarized optical needle with ultra-long depth of focus(DOF) is generated by tightly focusing a radially polarized beam that is modulated by a self-designed ternary hybrid(phase/amplitude) filter(THF). Both the phase and the amplitude patterns of THF are judiciously optimized by the versatile particle swarm optimization(PSO) searching algorithm. For the focusing configuration with a combination of a high numerical aperture(NA) and the optimized sine-shaped THFs, an optical needle with the full width at half maximum(FWHM) of 0.414λ and the DOF of 7.58λ is accessed, which corresponds to an aspect ratio of 18.3. The demonstrated longitudinally polarized super-resolution light needle with high aspect ratio opens up broad applications in high-density optical data storage, nano-photolithography, super-resolution imaging and high-efficiency particle trapping.
文摘The brightest flashlight named Imalent MS32 is capable of outputting up to 200,000 lumens of light,more than any other commercially available flashlight.Imagine having the ability to turn night into day in the palm of yourself and you kind of get a sense of what using the world's brightest flashlight feels and looks like.The Imalent MS32 is so incredibly powerful that the only other flashlight you can even compare it to is the Imalent MS18,the previous holder of the title of“world's brightest flashlight”.And that one was virtually half as powerful as the MS32,with a peak brightness of just 100,000 lumens.The LED‑powered light beam of the MS32 can reach as far as 1,618 meters and is the equivalent of 100 car lights in terms of brightness.
基金Supported by the National Natural Science Foundation of China under Grant No 60477041, the Key Project of Science and Technology of Fujian Province under Grant No 2007H0027, and the Foundation of Science and Technology Development of Southwest Jiaotong University of China under Grant No 2006B01.
文摘Based on vectorial Debye theory, tight focusing of radially and azimuthally polarized vortex beams passing through a dielectric interface are studied. The intensity distribution in the focal region is illustrated by numerical calculations. We show the influence of numerical-aperture （NA） on the full-width at half maximum （FWHM） of the focal spot or the focal hole. It has been found that compared with the azimuthally polarized Besse^Gaussian （BG） beams, the longitudinal component in the z direction of the radially polarized BG beams has no influence on the FWHM of the focal spot and hole, but enhances the total light intensity.
文摘Static strength finite element analysis was conducted to decrease the weight of a skeleton vehicle＇s frame. Results indicated that the maximum stress occurs on the front beam ＇s variable section area. Dynamic sensitivity analysis elucidated the relationship between the maximum stress and the thickness of a particular beam,e. g.,top,middle,and bottom beam. Displacement was analyzed by the key part that influenced the maximum stress. Finally,the new plan using BS960 super-high-strength beam steel and the preferred beam thickness was compared with the original plan. New combinations of beam thickness were introduced on the basis of different purposes; the maximum responding light w eight ratio was 21%.
基金supported by the National Natural Science Foundation of China(Grant Nos.62125503 and 62261160388)the Key R&D Program of Hubei Province of China(Grant Nos.2020BAB001 and 2021BAA024)+3 种基金the Key R&D Program of Guangdong Province(Grant No.2018B030325002)the Shenzhen Science and Technology Program(Grant No.JCYJ20200109114018750)the Open Projects Foundation of State Key Laboratory of Optical Fiber and Cable Manufacture Technology(Grant No.SKLD2201)the Innovation Project of Optics Valley Laboratory(Grant No.OVL2021BG004).
文摘Recently,structured light beams have attracted substantial attention in many applications,including optical communications,imaging,optical tweezers,and quantum optics.We propose and experimentally demonstrate a reconfigurable structured light beam generator in order to generate diverse structured light beams with adjustable beam types,beam orders,and beam sizes.By controlling the sizes of generated free-space structured light beams,free-space orbital angular momentum(OAM)beams and vector beams are coupled into an air-core fiber.To verify that our structured light generator enables generating structured light with high beam quality,polarization distributions and mode purity of generated OAM beams and vector beams in both free space and air-core fiber are characterized.Such a structured light generator may pave the way for future applications based on higher-order structured light beams.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674288)
文摘By using an amplitude-type spatial light modulator to load angular spectrum of Mathieu function distribution along a narrow annular pupils, the Durnin’s experimental setup is extended to generate various types of Mathieu beams. As a special type of Mathieu beams, Bessel beams are also generated using this optical setup. Furthermore, the optical morphology of the Mathieu beams family are also presented and analyzed.
基金supported by the National Natural Science Foundation of China (Grant No 60377025)Science and Technology Commission of Shanghai Municipal of China (Grant No 04JC14036)+1 种基金Shanghai Education Development Foundation of China (Grant No 2007CG52)the Shanghai Leading Academic Discipline Program of China (Grant No T0104)
文摘It is shown that a Gaussian light beam transmitting through a planar thin dielectric slab in the air undergoes four different effects, i.e. lateral Goos-Hanchen-like （GHL） displacement, angular deflection, width modification and longitudinal focal shift as compared with the results predicted by geometrical optics. According to the Taylor expansion of the exponent of transmission coefficient when expressed as an exponential form, the lateral GHL displacement and the angular deflection are the first-order effects and can be negative or positive. The width modification and the longitudinal focal shift are the second-order effects and can also be positive or negative. Owing to the waist-width dependent term, the non-geometrical effects of transmitted beam are not identical with the non-specular effects of reflected beam. The conditions for the validity of those effects are suggested and numerical simulations are also given.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10334110, 10634020, 60621063 and 10734130)National Basic Research Programme of China (Grant No 2007CB815101)the National Hi-Tech ICF Programme
文摘This paper analytically investigates the interaction of light filaments generated by a femtosecond laser beam in air. It obtains the Hamiltonian of a total laser field and interaction force between two filaments with different phase shifts and crossing angles. The property of the interaction force, which leads the attraction or repulsion of filaments, is basically dependent on the phase shift between filaments. The crossing angle between two filaments can only determine the magnitude of the interaction force, but does not change the property of the force.
