A new vibration technology with wide frequency band and wide amplitude rang is invented by research on chaos science.Four kinds of chaotic vibro-roller with China intellectual property are made for the first time in t...A new vibration technology with wide frequency band and wide amplitude rang is invented by research on chaos science.Four kinds of chaotic vibro-roller with China intellectual property are made for the first time in the world.It is proved that the working efficiency of a chaotic vibro-roller is 12.2% higher than that of a traditional one by check experiment.展开更多
The two-phase detection method for directional discrimination in laser Doppler measurements is discussed.The diffraction efficiency of a sin- gle period rectangular phase grating is analysed and a kind of back-scatter...The two-phase detection method for directional discrimination in laser Doppler measurements is discussed.The diffraction efficiency of a sin- gle period rectangular phase grating is analysed and a kind of back-scattered laser Doppler vibrometer without directional ambiguity using the single peri- od rectangular phase grating as the beam-combiner described.The principles of this kind of vibrometer are explained in detail,and some experimental re- sults are given.In this kind of vibrometer,the rectangular phase grating, without the zero diffracted order and even orders,is used to eliminate use- less stray light and to combine the useful signal light.Differential electronics is employed to reject signal noise.Therefore,the signal-to-noise ratio of Doppler signals and the measurement accuracy of the instrument are im- proved and the range of application is expanded.展开更多
Preparation of a high flux of hydrogen molecules in a specific vibrationally excited state is the major prerequisite and challenge in scattering experiments that use vibrationally excited hydrogen molecules as the tar...Preparation of a high flux of hydrogen molecules in a specific vibrationally excited state is the major prerequisite and challenge in scattering experiments that use vibrationally excited hydrogen molecules as the target. The widely used scheme of stimulated Raman pumping suffers from coherent population return which severely limits the excitation efficiency. Re- cently we successfully transferred D2 molecules in the molecular beam from （v=0, J=0） to （v=1, J=0） level, with the scheme of Stark-induced adiabatic Raman passage. As high as 75% of the excitation efficiency was achieved. This excitation technique promise to be a unique tool for crossed beam and beam-surface scattering experiments which aim to reveal the role of vibrational excitation of hydrogen molecules in the chemical reaction.展开更多
According to the design method of laser resonator cavity, we optimized the primary parameters of resonator and utilized LD arrays symmetrically pumping manner to implementing output of the high-brightness laser in our...According to the design method of laser resonator cavity, we optimized the primary parameters of resonator and utilized LD arrays symmetrically pumping manner to implementing output of the high-brightness laser in our laser cutter, then which was applied to precisely cutting the conductive film of CulnSe2 solar cells, the buried contact silicon solar cells＇ electrode groove, and perforating in wafer which is used to the emitter wrap through silicon solar cells. Laser processing precision was less than 40μm, the results have met solar cell＇s fabrication technology, and made fmally the buried cells＇ conversion efficiency be improved from 18% to 21%.展开更多
A direct prejudgement strategy that takes the diffraction ring as the analysis target is put forward to predict hot images induced by defects of tens of microns in the main amplifier section of high power laser system...A direct prejudgement strategy that takes the diffraction ring as the analysis target is put forward to predict hot images induced by defects of tens of microns in the main amplifier section of high power laser systems. Analysis of hot-image formation process shows that the hot image can be precisely calculated with the extracted intensity oscillation of the diffraction ring on the front surface of the nonlinear plate. The gradient direction matching （GDM） method is adopted to detect diffraction tings. Recognition of simulated diffraction rings shows that it is feasible to directly prejudge hot images induced by those closely spaced defects and the defects that are far apart from each other. Image compression and cluster analysis are utilized to optimize the performance of the GDM method in recognizing actually collected diffraction images. Results show that hot images induced by defects of tens of microns can be directly prejudged without redundant information.展开更多
The principle of optical trapping is conventionally based on the interaction of optical fields with linear-induced polarizations. However, the optical force originating from the nonlinear polarization becomes signific...The principle of optical trapping is conventionally based on the interaction of optical fields with linear-induced polarizations. However, the optical force originating from the nonlinear polarization becomes significant when nonlinear optical nanoparticles are trapped by femtosecond laser pulses. Herein we develop the time-averaged optical forces on a nonlinear optical nanoparticle using high-repetition-rate femtosecond laser pulses, based on the linear and nonlinear polarization effects. We investigate the dependence of the optical forces on the magnitudes and signs of the refractive nonlinearities. It is found that the self-focusing effect enhances the trapping ability, whereas the self-defocusing effect leads to the splitting of the potential well at the focal plane and destabilizes the optical trap. Our results show good agreement with the reported experimental observations and provide theoretical support for capturing nonlinear optical particles.展开更多
文摘A new vibration technology with wide frequency band and wide amplitude rang is invented by research on chaos science.Four kinds of chaotic vibro-roller with China intellectual property are made for the first time in the world.It is proved that the working efficiency of a chaotic vibro-roller is 12.2% higher than that of a traditional one by check experiment.
文摘The two-phase detection method for directional discrimination in laser Doppler measurements is discussed.The diffraction efficiency of a sin- gle period rectangular phase grating is analysed and a kind of back-scattered laser Doppler vibrometer without directional ambiguity using the single peri- od rectangular phase grating as the beam-combiner described.The principles of this kind of vibrometer are explained in detail,and some experimental re- sults are given.In this kind of vibrometer,the rectangular phase grating, without the zero diffracted order and even orders,is used to eliminate use- less stray light and to combine the useful signal light.Differential electronics is employed to reject signal noise.Therefore,the signal-to-noise ratio of Doppler signals and the measurement accuracy of the instrument are im- proved and the range of application is expanded.
文摘Preparation of a high flux of hydrogen molecules in a specific vibrationally excited state is the major prerequisite and challenge in scattering experiments that use vibrationally excited hydrogen molecules as the target. The widely used scheme of stimulated Raman pumping suffers from coherent population return which severely limits the excitation efficiency. Re- cently we successfully transferred D2 molecules in the molecular beam from （v=0, J=0） to （v=1, J=0） level, with the scheme of Stark-induced adiabatic Raman passage. As high as 75% of the excitation efficiency was achieved. This excitation technique promise to be a unique tool for crossed beam and beam-surface scattering experiments which aim to reveal the role of vibrational excitation of hydrogen molecules in the chemical reaction.
基金This work was supported by the Student’s Innovating Foundationin Nankai University.
文摘According to the design method of laser resonator cavity, we optimized the primary parameters of resonator and utilized LD arrays symmetrically pumping manner to implementing output of the high-brightness laser in our laser cutter, then which was applied to precisely cutting the conductive film of CulnSe2 solar cells, the buried contact silicon solar cells＇ electrode groove, and perforating in wafer which is used to the emitter wrap through silicon solar cells. Laser processing precision was less than 40μm, the results have met solar cell＇s fabrication technology, and made fmally the buried cells＇ conversion efficiency be improved from 18% to 21%.
基金supported by the International Partnership Program of Chinese Academy Of Sciences(No.181231KYSB20170022)the National Natural Science Foundation of China(No.11774364)the Shanghai Sailing Program(No.18YF1425900)
文摘A direct prejudgement strategy that takes the diffraction ring as the analysis target is put forward to predict hot images induced by defects of tens of microns in the main amplifier section of high power laser systems. Analysis of hot-image formation process shows that the hot image can be precisely calculated with the extracted intensity oscillation of the diffraction ring on the front surface of the nonlinear plate. The gradient direction matching （GDM） method is adopted to detect diffraction tings. Recognition of simulated diffraction rings shows that it is feasible to directly prejudge hot images induced by those closely spaced defects and the defects that are far apart from each other. Image compression and cluster analysis are utilized to optimize the performance of the GDM method in recognizing actually collected diffraction images. Results show that hot images induced by defects of tens of microns can be directly prejudged without redundant information.
基金National Natural Science Foundation of China(NSFC)(11474052,11504049,11774055,61535003)Natural Science Foundation of Jiangsu Province,China(BK20171364)National Key Basic Research Program of China(2015CB352002)
文摘The principle of optical trapping is conventionally based on the interaction of optical fields with linear-induced polarizations. However, the optical force originating from the nonlinear polarization becomes significant when nonlinear optical nanoparticles are trapped by femtosecond laser pulses. Herein we develop the time-averaged optical forces on a nonlinear optical nanoparticle using high-repetition-rate femtosecond laser pulses, based on the linear and nonlinear polarization effects. We investigate the dependence of the optical forces on the magnitudes and signs of the refractive nonlinearities. It is found that the self-focusing effect enhances the trapping ability, whereas the self-defocusing effect leads to the splitting of the potential well at the focal plane and destabilizes the optical trap. Our results show good agreement with the reported experimental observations and provide theoretical support for capturing nonlinear optical particles.
