Based on the paraxial wave equation,this study extends the theory of small-scale self-focusing(SSSF)from coherent beams to spatially partially coherent beams(PCBs)and derives a general theoretical equation that reveal...Based on the paraxial wave equation,this study extends the theory of small-scale self-focusing(SSSF)from coherent beams to spatially partially coherent beams(PCBs)and derives a general theoretical equation that reveals the underlying physics of the reduction in the B-integral of spatially PCBs.From the analysis of the simulations,the formula for the modulational instability(MI)gain coefficient of the SSSF of spatially PCBs is obtained by introducing a decrease factor into the formula of the MI gain coefficient of the SSSF of coherent beams.This decrease can be equated to a drop in the injected light intensity or an increase in the critical power.According to this formula,the reference value of the spatial coherence of spatially PCBs is given,offering guidance to overcome the output power limitation of the high-power laser driver due to SSSF.展开更多
In this study, we explore the far-zero behaviors of a scattered partially polarized spatially and spectrally partially coherent electromagnetic pulsed beam irradiating on a deterministic medium. The analytical formula...In this study, we explore the far-zero behaviors of a scattered partially polarized spatially and spectrally partially coherent electromagnetic pulsed beam irradiating on a deterministic medium. The analytical formula for the cross-spectral density matrix elements of this beam in the spherical coordinate system is derived. Within the framework of the first-order Born approximation, the effects of the scattering angle θ, the source parameters (i.e., the pulse duration T0 and the temporal coherence length Tcxx), and the scatterer parameter (i.e., the effective width of the medium σR) on the spectral density, the spectral shift, the spectral degree of polarization, and the degree of spectral coherence of the scattered source in the far-zero field are studied numerically and comparatively. Our work improves the scattering theory of stochastic electromagnetic beams and it may be useful for the applications involving the interaction between incident light waves and scattering media.展开更多
Using the mutually coherent function, the self-trapping of the circle partially coherent optical beam in the total internal reflective photonic crystal fiber(TIRPCF) under Compton scattering is studied. The study show...Using the mutually coherent function, the self-trapping of the circle partially coherent optical beam in the total internal reflective photonic crystal fiber(TIRPCF) under Compton scattering is studied. The study shows that the composition of the non-coherent optical beam in the optical spectrum and the diffraction effect are decreased by Compton scattering, and the probability of forming the soliton is greatly increased. The vibration peak value in the propagation, compressed degree, changed cycle, and radius of the soliton are all smaller than those before the scattering, but its coherent radius is larger than that before the scattering. In this propagation, the self-focusing plays a key role.展开更多
文摘Based on the paraxial wave equation,this study extends the theory of small-scale self-focusing(SSSF)from coherent beams to spatially partially coherent beams(PCBs)and derives a general theoretical equation that reveals the underlying physics of the reduction in the B-integral of spatially PCBs.From the analysis of the simulations,the formula for the modulational instability(MI)gain coefficient of the SSSF of spatially PCBs is obtained by introducing a decrease factor into the formula of the MI gain coefficient of the SSSF of coherent beams.This decrease can be equated to a drop in the injected light intensity or an increase in the critical power.According to this formula,the reference value of the spatial coherence of spatially PCBs is given,offering guidance to overcome the output power limitation of the high-power laser driver due to SSSF.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11504286)the Natural Science Basic Research Program of Shaanxi Province, China (Grant No. 2019JM-470)+1 种基金the Fund from the International Technology Collaborative Center for Advanced Optical Manufacturing and Optoelectronic Measurementthe Science Fund from the Shaanxi Provincial Key Laboratory of Photoelectric Measurement and Instrument Technology.
文摘In this study, we explore the far-zero behaviors of a scattered partially polarized spatially and spectrally partially coherent electromagnetic pulsed beam irradiating on a deterministic medium. The analytical formula for the cross-spectral density matrix elements of this beam in the spherical coordinate system is derived. Within the framework of the first-order Born approximation, the effects of the scattering angle θ, the source parameters (i.e., the pulse duration T0 and the temporal coherence length Tcxx), and the scatterer parameter (i.e., the effective width of the medium σR) on the spectral density, the spectral shift, the spectral degree of polarization, and the degree of spectral coherence of the scattered source in the far-zero field are studied numerically and comparatively. Our work improves the scattering theory of stochastic electromagnetic beams and it may be useful for the applications involving the interaction between incident light waves and scattering media.
基金Natural Science Basic Research Project for Education Depart ment of Henan Province Natural ScienceFoundation of Zhumadian City(058001)
文摘Using the mutually coherent function, the self-trapping of the circle partially coherent optical beam in the total internal reflective photonic crystal fiber(TIRPCF) under Compton scattering is studied. The study shows that the composition of the non-coherent optical beam in the optical spectrum and the diffraction effect are decreased by Compton scattering, and the probability of forming the soliton is greatly increased. The vibration peak value in the propagation, compressed degree, changed cycle, and radius of the soliton are all smaller than those before the scattering, but its coherent radius is larger than that before the scattering. In this propagation, the self-focusing plays a key role.
文摘光束在大气湍流中传输时,大气湍流效应对光束进行强度和相位的随机调制,最终在远场处形成散斑。以部分相干高斯-谢尔模型(Gaussian-Schell Model,GSM)光束为研究对象,根据广义的HuygensFresnel原理、修正Von Karman谱模型,推导了GSM光束在大气湍流中传输时接收端光束的有效半径和平均散斑半径的表达式。利用数值计算对比分析光源相关参数和大气湍流对光束有效半径和平均散斑半径的影响。研究表明:光束的初始束腰半径越大、相干长度越小以及波长越小时,接收端光束的有效半径和平均散斑半径受湍流的影响越小;大气折射率结构常数越大,光束扩展越严重,此时平均散斑半径越小;光束有效半径和平均散斑半径随湍流外尺度增大几乎无变化,随湍流内尺度的增大而减小。所得出的结论对无线激光通信系统中光束的捕获、对准与跟踪(Acquisition,Pointing and Tracking,APT)系统的设计提供一个重要的参考价值。
