The propagation properties of partially coherent Hermite-Gaussian beams through non-Kolmogorov atmospheric turbulence are studied. The effects of non-Kolmogorov turbulence and beam nonparaxiality on the average intens...The propagation properties of partially coherent Hermite-Gaussian beams through non-Kolmogorov atmospheric turbulence are studied. The effects of non-Kolmogorov turbulence and beam nonparaxiality on the average intensity evolution and the beam-width spreading are stressed. It is found that the evolution of the average intensity distribution and the beam-width spreading depends on the generalized exponent factor, namely, on the non-Kolmogorov turbulence strength for the paraxial case. For the non-paraxial case the effect of the turbulence is negiigibl% while the beam-width spreading becomes very large. The analytical results are illustrated numerically and interpreted physically.展开更多
Taking partially coherent cosh-Gaussian （ChG） beams as an example of more general partially coherent beams, we have studied the spectral degree of coherence of partially coherent ChG beams in the far field. It is sh...Taking partially coherent cosh-Gaussian （ChG） beams as an example of more general partially coherent beams, we have studied the spectral degree of coherence of partially coherent ChG beams in the far field. It is shown that, unlike Gaussian Schell-model （GSM） beams, in the strict sense there do not exist two partially coherent ChG beams which can generate far fields with the same spectral degree of coherence. However, under certain conditions it is possible to find two partially coherent ChG beams with the same spectral degree of coherence in the far field.展开更多
Based on the integral representation of the Bessel functions and the generating function of the Tricomi function, an analytical expression of the Wigner distribution function （WDF） for a coherent or partially cohere...Based on the integral representation of the Bessel functions and the generating function of the Tricomi function, an analytical expression of the Wigner distribution function （WDF） for a coherent or partially coherent Bessel Gaussian beam is presented. The reduced two-dimensional WDFs are also demonstrated graphically, which reveals the dependence of the reduced WDFs on the beam parameters.展开更多
Based on the propagation law of cross-spectral density function, studied in this paper are the coherence vortices of partially coherent, quasi-monochromatic singular beams with Gaussian envelope and Schell-model corre...Based on the propagation law of cross-spectral density function, studied in this paper are the coherence vortices of partially coherent, quasi-monochromatic singular beams with Gaussian envelope and Schell-model correlator in the far field, where our main attention is paid to the evolution of far-field coherence vortices into intensity vortices of fully coherent beams. The results show that, although there are usually no zeros of intensity in partially coherent beams with Gaussian envelope and Schell-model correlator~ zeros of spectral degree of coherence exist. The coherence vortices of spectral degree of coherence depend on the relative coherence length, mode index and positions of pairs of points. If a point and mode index are kept fixed, the position of coherence vortices changes with the increase of the relative coherence length. For the low coherent case there is a circular phase dislocation. In the coherent limit coherence vortices become intensity vortices of fully coherent Laguerre-Gaussian beams.展开更多
The propagation performance of high-power partially coherent fibre laser beams in a real environment is inves- tigated and the theoretical model of a high-power fibre laser propagating in a real environment is establi...The propagation performance of high-power partially coherent fibre laser beams in a real environment is inves- tigated and the theoretical model of a high-power fibre laser propagating in a real environment is established. The influence of a collimating system and thermal blooming is considered together with atmospheric turbulence and me- chanical jitter. The laser energy concentration of partially coherent beams in the far field is calculated and analysed based on the theoretical model. It is shown that the propagation performance of partially coherent beams depends on the collimating system, atmospheric turbulence, mechanical jitter and thermal blooming. The propagation performance of partially coherent beams and fully coherent beams is studied and the results show that partially coherent beams are less sensitive to the influence of thermal blooming, which results in that the energy degeneration for partially coherent beams is only 50% of that for fully coherent beams. Both partially coherent beams and fully coherent beams become less sensitive to thermal blooming when the average structural constant of the refraction index fluctuations increases to 1.7×10^-14 m^-2/3. The investigation presents a reference for applications of a high-power fibre laser system.展开更多
The self-focusing phenomenon of partially coherent beams(PCBs)was simulated using the complex screen method combined with the split-step Fourier method to solve the nonlinear Schrödinger equation.Considering the ...The self-focusing phenomenon of partially coherent beams(PCBs)was simulated using the complex screen method combined with the split-step Fourier method to solve the nonlinear Schrödinger equation.Considering the propagation of Gaussian Schell-model beams in a nonlinear medium as an example,the suppression effects of intensity,propagation distance,and spatial coherence on small-scale self-focusing were demonstrated.Simulations of overall and small-scale self-focusing using this method were compared with the existing literature to demonstrate the validity of the method.This method can numerically analyze the degree of self-focusing in PCBs and advance the study of their nonlinearity.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No.10874125)
文摘The propagation properties of partially coherent Hermite-Gaussian beams through non-Kolmogorov atmospheric turbulence are studied. The effects of non-Kolmogorov turbulence and beam nonparaxiality on the average intensity evolution and the beam-width spreading are stressed. It is found that the evolution of the average intensity distribution and the beam-width spreading depends on the generalized exponent factor, namely, on the non-Kolmogorov turbulence strength for the paraxial case. For the non-paraxial case the effect of the turbulence is negiigibl% while the beam-width spreading becomes very large. The analytical results are illustrated numerically and interpreted physically.
基金supported by the National Natural Science Foundation of China (Grant Nos 10574097 and 10874125)
文摘Taking partially coherent cosh-Gaussian （ChG） beams as an example of more general partially coherent beams, we have studied the spectral degree of coherence of partially coherent ChG beams in the far field. It is shown that, unlike Gaussian Schell-model （GSM） beams, in the strict sense there do not exist two partially coherent ChG beams which can generate far fields with the same spectral degree of coherence. However, under certain conditions it is possible to find two partially coherent ChG beams with the same spectral degree of coherence in the far field.
文摘Based on the integral representation of the Bessel functions and the generating function of the Tricomi function, an analytical expression of the Wigner distribution function （WDF） for a coherent or partially coherent Bessel Gaussian beam is presented. The reduced two-dimensional WDFs are also demonstrated graphically, which reveals the dependence of the reduced WDFs on the beam parameters.
基金Project supported by the National Natural Science Foundation of China （Grant No 10574097）.
文摘Based on the propagation law of cross-spectral density function, studied in this paper are the coherence vortices of partially coherent, quasi-monochromatic singular beams with Gaussian envelope and Schell-model correlator in the far field, where our main attention is paid to the evolution of far-field coherence vortices into intensity vortices of fully coherent beams. The results show that, although there are usually no zeros of intensity in partially coherent beams with Gaussian envelope and Schell-model correlator~ zeros of spectral degree of coherence exist. The coherence vortices of spectral degree of coherence depend on the relative coherence length, mode index and positions of pairs of points. If a point and mode index are kept fixed, the position of coherence vortices changes with the increase of the relative coherence length. For the low coherent case there is a circular phase dislocation. In the coherent limit coherence vortices become intensity vortices of fully coherent Laguerre-Gaussian beams.
文摘The propagation performance of high-power partially coherent fibre laser beams in a real environment is inves- tigated and the theoretical model of a high-power fibre laser propagating in a real environment is established. The influence of a collimating system and thermal blooming is considered together with atmospheric turbulence and me- chanical jitter. The laser energy concentration of partially coherent beams in the far field is calculated and analysed based on the theoretical model. It is shown that the propagation performance of partially coherent beams depends on the collimating system, atmospheric turbulence, mechanical jitter and thermal blooming. The propagation performance of partially coherent beams and fully coherent beams is studied and the results show that partially coherent beams are less sensitive to the influence of thermal blooming, which results in that the energy degeneration for partially coherent beams is only 50% of that for fully coherent beams. Both partially coherent beams and fully coherent beams become less sensitive to thermal blooming when the average structural constant of the refraction index fluctuations increases to 1.7×10^-14 m^-2/3. The investigation presents a reference for applications of a high-power fibre laser system.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDA25020203 and 25020301)the Innovation Fund of the Key Laboratory of the Chinese Academy of Sciences(No.CXJJ-21S015)。
文摘The self-focusing phenomenon of partially coherent beams(PCBs)was simulated using the complex screen method combined with the split-step Fourier method to solve the nonlinear Schrödinger equation.Considering the propagation of Gaussian Schell-model beams in a nonlinear medium as an example,the suppression effects of intensity,propagation distance,and spatial coherence on small-scale self-focusing were demonstrated.Simulations of overall and small-scale self-focusing using this method were compared with the existing literature to demonstrate the validity of the method.This method can numerically analyze the degree of self-focusing in PCBs and advance the study of their nonlinearity.
