Combined with the optical beam deflection,a novel approach of phase matched broadband scanning optical parametric chirped pulse amplification(OPCPA)was proposed.For this scheme,there was no superfluous operations to t...Combined with the optical beam deflection,a novel approach of phase matched broadband scanning optical parametric chirped pulse amplification(OPCPA)was proposed.For this scheme,there was no superfluous operations to the chirped signal pulse which propagated in a changeless direction straightforward,but the pump beam were deflected in space with time by passing through a KTN crystal,which was applied with varied driving voltage.The theories of phase matching of each chirped signal frequency based on pump beam deflection was analyzed detailedly.And the type-I amplification of chirped signal with 800 nm central wavelength and 20 nm bandwidth pumped by 532 nm in BBO crystal was simulated as a case in point.The simulation results showed that the spectral distribution of chirped signal pulse was almost the same as the initial form,i.e.,there was nearly no narrowing on the amplified spectrum by using of the scanning OPCPA based on pump beam deflection.In addition,the simulations demonstrated that it was worth minimizing the voltage deviation applied to KTN crystal as much as possible for the sake of better waveform,larger bandwidth and higher conversion efficiency of amplified signal pulse in the proposed scanning OPCPA.展开更多
By using the expressions of the field parameters and with the aid of the Orthogonal DesignMethod,we optimized the design of the saddle delection yoke with a ferromagnetic shield.The results ob-tained agree with the pr...By using the expressions of the field parameters and with the aid of the Orthogonal DesignMethod,we optimized the design of the saddle delection yoke with a ferromagnetic shield.The results ob-tained agree with the practical model.It is pointed out that the end ear and the distribution of the fieldparameter B<sub>0</sub>（z）have important effects on the deflection aberrations.An example is given,in which the elec-tron optical properties of the deflection coils having cosine distribution and finite length and that of the de-flection coils having distributed winding are compared.展开更多
The beam deflectors based on electro-optic phased array(EOPA) is mainly described, and then an analysis on existing control schemes for driving the EOPA beam deflectors, based on custom hard-wired electronics or based...The beam deflectors based on electro-optic phased array(EOPA) is mainly described, and then an analysis on existing control schemes for driving the EOPA beam deflectors, based on custom hard-wired electronics or based on software in a microcontroller, is made. Compared with these, a driving and control system for a multi-channel EOPA beam deflector is presented, in which the control assignment is implemented with a field programmable gate array(FPGA) chip. For different performance requirements, two control schemes, one with the serial scheme and another with the parallel scheme, have been explored and rapidly prototyped in Xilinx FPGA chips. With the control structures for the EOPA beam deflector, scanning rates of 588kHz and 5MHz can be respectively reached.展开更多
This paper presents the technique of step acousto-optical deflection and its application in high speed interferometric photography. When a light beam carrying the interferogram information passes through an acousto-op...This paper presents the technique of step acousto-optical deflection and its application in high speed interferometric photography. When a light beam carrying the interferogram information passes through an acousto-optical deflector, it is deflected into 10 patterns (φ6 mm-φ8 mm in diameter) in time-sequence and recorded on a fixed film under the action of step pulsed ultrasonic waves. The exposure time of every pattern is adjustable within the range of 10^(-5)-3 ×10^(-6) s and the interval between two patterns is 10^(-5) s. The multi-frame interferograms of the transient combustion field of the first fire composition ignited by laser are recorded by using this method with combination of a laser interferometer, and the temperature distribution and its change with time is calculated quantitatively.展开更多
直通光路型磁光式光学电流传感器(magneto-optical current sensor,MOCS)因具有体积小,测量准确度高等多种优点,在智能电网中有广阔应用前景。然而,由于无法构成闭合光路,外磁场干扰一直是制约直通光路型磁光式光学电流传感器实用化的...直通光路型磁光式光学电流传感器(magneto-optical current sensor,MOCS)因具有体积小,测量准确度高等多种优点,在智能电网中有广阔应用前景。然而,由于无法构成闭合光路,外磁场干扰一直是制约直通光路型磁光式光学电流传感器实用化的重要因素。为解决此问题,该文提出光学电流传感层叠抗外磁干扰技术。首先通过定义非连续积分路径,积分张角等概念,推导出电流位于非连续闭合路径内外时对应的磁场积分表达式,进而建立适用于含任意数量磁光传感单元、按对称多边形方式布置的MOCS所受外磁干扰分析的数学模型,提出闭合路径中心偏转模型,并得出最佳中心偏转角。在此基础上提出一种新型的层叠式MOCS结构,基本抗御传感结构外任意位置电流给MOCS带来的磁场干扰。其次,提出通用的层叠式MOCS测量误差分析方法,从理论上证明层叠式MOCS满足工程需求及标准。分别建立层叠式MOCS数值仿真模型及COMSOL有限元仿真模型。仿真结果表明,在不同干扰条件下,层叠式MOCS的测量误差均低于0.2%,证明此结构能够有效降低存在外磁干扰时MOCS的测量误差。最后,设计并搭建相应的层叠式MOCS实验平台并进行相应实验。实验结果表明,新型层叠式MOCS在多种干扰情况下其测量误差均小于0.2%,证明了所提数学模型正确性及层叠式结构应用于提高MOCS抗外磁干扰能力时的有效性。展开更多
Flat metaoptics components are looking to replace classical optics elements and could lead to extremely compact biophotonics devices if integrated with on-chip light sources and detectors.However,using metasurfaces to...Flat metaoptics components are looking to replace classical optics elements and could lead to extremely compact biophotonics devices if integrated with on-chip light sources and detectors.However,using metasurfaces to shape light into wide angular range wavefronts with high efficiency,as is typically required in high-contrast microscopy applications,remains a challenge.Here we demonstrate curved GaAs metagratings integrated on vertical-cavity surface-emitting lasers(VCSELs)that enable on-chip illumination in total internal reflection and dark field microscopy.Based on an unconventional design that circumvents the aspect ratio dependent etching problems in monolithic integration,we demonstrate off-axis emission centred at 60°in air and 63°in glass with>90%and>70%relative deflection efficiency,respectively.The resulting laser beam is collimated out-of-plane but maintains Gaussian divergence in-plane,resulting in a long and narrow illumination area.We show that metagrating-integrated VCSELs of different kinds can be combined to enable rapid switching between dark-field and total internal reflection illumination.Our approach provides a versatile illumination solution for high-contrast imaging that is compatible with conventional microscopy setups and can be integrated with biophotonics devices,such as portable microscopy,NIR-II range bioimaging,and lab-on-a-chip devices.展开更多
The temperature effects on the evolution and self-deflection of bright spatial optical solitons in photo-voltaic photorefractive media were investigated by taking into account diffusion effects. The numerical results ...The temperature effects on the evolution and self-deflection of bright spatial optical solitons in photo-voltaic photorefractive media were investigated by taking into account diffusion effects. The numerical results show that the evolution of the bright solitary beam depends strongly on the crystal temperature. It is also found that the bending distance of the bright solitary beam centre increases and reaches its maximum value at a characteristic temperature, and then decreases as temperature rises and ap-proaches zero at low and high temperatures. Both the maximum value and characteristic temperature increase with the input power density. The self-deflection of bright solitary beam is further studied by a perturbation technique, and the results are found to be in good agreement with that obtained by the numerical method. The diffusion process and the dark irradiance dominate the temperature depend-ence of bending distance in most values of temperature besides at the characteristic temperature and in the higher temperature regime. The diffusion process will mainly dominate the temperature dependence at the characteristic temperature and the dark irradiance will dominate in the higher tem-perature range.展开更多
基金supported by Science and Technology Innovation Seedling Project of Sichuan Province,China(Grant No.2018100)Major Project of CDNU(Grant No.CS18ZDZ0511).
文摘Combined with the optical beam deflection,a novel approach of phase matched broadband scanning optical parametric chirped pulse amplification(OPCPA)was proposed.For this scheme,there was no superfluous operations to the chirped signal pulse which propagated in a changeless direction straightforward,but the pump beam were deflected in space with time by passing through a KTN crystal,which was applied with varied driving voltage.The theories of phase matching of each chirped signal frequency based on pump beam deflection was analyzed detailedly.And the type-I amplification of chirped signal with 800 nm central wavelength and 20 nm bandwidth pumped by 532 nm in BBO crystal was simulated as a case in point.The simulation results showed that the spectral distribution of chirped signal pulse was almost the same as the initial form,i.e.,there was nearly no narrowing on the amplified spectrum by using of the scanning OPCPA based on pump beam deflection.In addition,the simulations demonstrated that it was worth minimizing the voltage deviation applied to KTN crystal as much as possible for the sake of better waveform,larger bandwidth and higher conversion efficiency of amplified signal pulse in the proposed scanning OPCPA.
文摘By using the expressions of the field parameters and with the aid of the Orthogonal DesignMethod,we optimized the design of the saddle delection yoke with a ferromagnetic shield.The results ob-tained agree with the practical model.It is pointed out that the end ear and the distribution of the fieldparameter B<sub>0</sub>（z）have important effects on the deflection aberrations.An example is given,in which the elec-tron optical properties of the deflection coils having cosine distribution and finite length and that of the de-flection coils having distributed winding are compared.
基金National Natural Science Foundation of China(60477042)
文摘The beam deflectors based on electro-optic phased array(EOPA) is mainly described, and then an analysis on existing control schemes for driving the EOPA beam deflectors, based on custom hard-wired electronics or based on software in a microcontroller, is made. Compared with these, a driving and control system for a multi-channel EOPA beam deflector is presented, in which the control assignment is implemented with a field programmable gate array(FPGA) chip. For different performance requirements, two control schemes, one with the serial scheme and another with the parallel scheme, have been explored and rapidly prototyped in Xilinx FPGA chips. With the control structures for the EOPA beam deflector, scanning rates of 588kHz and 5MHz can be respectively reached.
文摘This paper presents the technique of step acousto-optical deflection and its application in high speed interferometric photography. When a light beam carrying the interferogram information passes through an acousto-optical deflector, it is deflected into 10 patterns (φ6 mm-φ8 mm in diameter) in time-sequence and recorded on a fixed film under the action of step pulsed ultrasonic waves. The exposure time of every pattern is adjustable within the range of 10^(-5)-3 ×10^(-6) s and the interval between two patterns is 10^(-5) s. The multi-frame interferograms of the transient combustion field of the first fire composition ignited by laser are recorded by using this method with combination of a laser interferometer, and the temperature distribution and its change with time is calculated quantitatively.
文摘直通光路型磁光式光学电流传感器(magneto-optical current sensor,MOCS)因具有体积小,测量准确度高等多种优点,在智能电网中有广阔应用前景。然而,由于无法构成闭合光路,外磁场干扰一直是制约直通光路型磁光式光学电流传感器实用化的重要因素。为解决此问题,该文提出光学电流传感层叠抗外磁干扰技术。首先通过定义非连续积分路径,积分张角等概念,推导出电流位于非连续闭合路径内外时对应的磁场积分表达式,进而建立适用于含任意数量磁光传感单元、按对称多边形方式布置的MOCS所受外磁干扰分析的数学模型,提出闭合路径中心偏转模型,并得出最佳中心偏转角。在此基础上提出一种新型的层叠式MOCS结构,基本抗御传感结构外任意位置电流给MOCS带来的磁场干扰。其次,提出通用的层叠式MOCS测量误差分析方法,从理论上证明层叠式MOCS满足工程需求及标准。分别建立层叠式MOCS数值仿真模型及COMSOL有限元仿真模型。仿真结果表明,在不同干扰条件下,层叠式MOCS的测量误差均低于0.2%,证明此结构能够有效降低存在外磁干扰时MOCS的测量误差。最后,设计并搭建相应的层叠式MOCS实验平台并进行相应实验。实验结果表明,新型层叠式MOCS在多种干扰情况下其测量误差均小于0.2%,证明了所提数学模型正确性及层叠式结构应用于提高MOCS抗外磁干扰能力时的有效性。
基金This work was funded by the Knut and Alice Wallenberg Foundation and performed in part at Myfab Chalmers.The authors acknowledge Emelie Tornéus for assistance preparing the cell samples and Ruggero Verre for assistance with the nanofabrication.Cell samples were a kind gift from Caroline Adiels.Nanorods were synthesized by Lei Shao.
文摘Flat metaoptics components are looking to replace classical optics elements and could lead to extremely compact biophotonics devices if integrated with on-chip light sources and detectors.However,using metasurfaces to shape light into wide angular range wavefronts with high efficiency,as is typically required in high-contrast microscopy applications,remains a challenge.Here we demonstrate curved GaAs metagratings integrated on vertical-cavity surface-emitting lasers(VCSELs)that enable on-chip illumination in total internal reflection and dark field microscopy.Based on an unconventional design that circumvents the aspect ratio dependent etching problems in monolithic integration,we demonstrate off-axis emission centred at 60°in air and 63°in glass with>90%and>70%relative deflection efficiency,respectively.The resulting laser beam is collimated out-of-plane but maintains Gaussian divergence in-plane,resulting in a long and narrow illumination area.We show that metagrating-integrated VCSELs of different kinds can be combined to enable rapid switching between dark-field and total internal reflection illumination.Our approach provides a versatile illumination solution for high-contrast imaging that is compatible with conventional microscopy setups and can be integrated with biophotonics devices,such as portable microscopy,NIR-II range bioimaging,and lab-on-a-chip devices.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 10574051, 10174025)Natural Science Foundation of Hubei Province (Grant No. 2008CDB005)Research Foundation for Outstanding Young Teachers, China University of Geosciences (Wuhan)
文摘The temperature effects on the evolution and self-deflection of bright spatial optical solitons in photo-voltaic photorefractive media were investigated by taking into account diffusion effects. The numerical results show that the evolution of the bright solitary beam depends strongly on the crystal temperature. It is also found that the bending distance of the bright solitary beam centre increases and reaches its maximum value at a characteristic temperature, and then decreases as temperature rises and ap-proaches zero at low and high temperatures. Both the maximum value and characteristic temperature increase with the input power density. The self-deflection of bright solitary beam is further studied by a perturbation technique, and the results are found to be in good agreement with that obtained by the numerical method. The diffusion process and the dark irradiance dominate the temperature depend-ence of bending distance in most values of temperature besides at the characteristic temperature and in the higher temperature regime. The diffusion process will mainly dominate the temperature dependence at the characteristic temperature and the dark irradiance will dominate in the higher tem-perature range.
基金The Young Junior Faculties Programme of Education Department of Henan Province(No.2011GGJS-081)the Project in Natural Science Research Foundation of Education Department of Henan Province(No.2010A510002)
