共查询到16条相似文献,搜索用时 93 毫秒
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自聚焦透镜的三维相干成像特性分析 总被引:2,自引:1,他引:2
运用傅里叶光学方法,分析并推导了自聚焦透镜的三维相干成像公式。研究表明,虽然自聚焦透镜中介质折射率是径向渐变折射率分布,不同于薄透镜中的均匀分布,但是由于它的三维相干成像性质却类似于薄透镜,从而使自聚焦透镜可以在成像和光学信息处理系统中有效地代替薄透镜,实现光学系统的微型化。 相似文献
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A seed laser oscillating at different frequencies is proved to have the potential to mitigate the stimulated Brillouin scattering(SBS) effect in a fiber amplifier,which may increase the emission power of a coherent beam combination(CBC) system greatly.In this study,a basic mathematical model describing the multi-wavelength CBC is proposed on the fundamentals of CBC.A useful method for estimating the combination effect and analysing the feasibility and the validity of the multi-wavelength coherent combination is provided.In the numerical analysis,accordant results with four-wavelength four-channel CBC experiments are obtained.Through calculations of some examples with certain spectra,the unanticipated excellent combination effect with a few frequencies involved is explained,and the dependence of the combination effect on the variance of the amplifier chain length and the channel number is clarified. 相似文献
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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. 相似文献
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Influence of optical nonlinearity on combining efficiency in ultrashort pulse fiber laser coherent combining system 下载免费PDF全文
Yun-Chen Zhu 《中国物理 B》2022,31(6):64201-064201
The influence of optical nonlinearity on combining efficiency in ultrashort pulse fiber laser coherent combining system is investigated theoretically and experimentally. In the theoretical work, a new theoretical algorithm is presented for the coherent combining efficiency, which can be used to quantify the spectral coherence decay induced by optical nonlinearity imbalance between the sub-beams. The spectral information of the sub-beam is obtained by numerically solving the nonlinear Schrödinger equation (NLSE) in this algorithm to ensure an accurate prediction. In the experimental work, the coherent combining of two all-fiber picosecond lasers is achieved, and the influence of imbalanced optical nonlinearity on the combining efficiency is studied, which agrees with the theoretical prediction. This paper reveals the physical mechanism for the influence of optical nonlinearity on the combining efficiency, which is valuable for the coherent combining of ultrashort pulse fiber laser beams. 相似文献