scholarly journals Generation of an Adjustable Optical Cage through Focusing an Apertured Bessel-Gaussian Correlated Schell-Model Beam

2019 ◽  
Vol 9 (3) ◽  
pp. 550 ◽  
Author(s):  
Lina Guo ◽  
Li Chen ◽  
Rong Lin ◽  
Minghui Zhang ◽  
Yaru Gao ◽  
...  
Keyword(s):  
Thermal Processing ◽  
Gaussian Function ◽  
Spatial Coherence ◽  
Analytical Formula ◽  
Coherent Beam ◽  
Beam Size ◽  
Degree Of Coherence ◽  
Spectral Degree ◽  
Coherence Width ◽  
Effective Beam

An adjustable optical cage generated by focusing a partially coherent beam with nonconventional correlation function named the Bessel–Gaussian correlated Schell-model (BGCSM) beam is investigated in detail. With the help of the generalized Huygens–Fresnel integral and complex Gaussian function expansion, the analytical formula of the BGCSM beam passing through an apertured ABCD optical system was derived. Our numerical results show that the generated optical cage can be moderately adjusted by the aperture radius, the spatial coherence width, and the parameter β of the BGCSM beam. Furthermore, the effect of these parameters on the effective beam size and the spectral degree of coherence were also analyzed. The optical cage with adjustable size can be applied for particle trapping and material thermal processing.

scholarly journals Generation and Propagation of a Hermite-Gaussian Correlated Schell-Model LG0l Beam

2019 ◽  
Vol 9 (3) ◽  
pp. 610 ◽  
Author(s):  
Xiaofeng Peng ◽  
Xingyuan Lu ◽  
Xianlong Liu ◽  
Chenliang Zhao ◽  
Rong Lin ◽  
...  
Keyword(s):  
Coherence Length ◽  
Coherent Beam ◽  
Statistical Properties ◽  
Vortex Phase ◽  
Partially Coherent ◽  
Degree Of Coherence ◽  
Combined Action ◽  
Coherence Width

A partially coherent beam under the combined action of a Hermite-Gaussian correlated function and vortex phase, named the HGCSMLG0l beam has been explored both theoretically and experimentally. The statistical properties, such as the intensity and distribution of the degree of coherence (DOC) on propagation are analyzed in detail, based on the deduced equations. We find that the intensity is determined dominantly by the non-conventional correlated function when the coherence length is comparatively small and by vortex phase when the coherence length is large. The modulus of the DOC is not vulnerable to coherence width, rather, it is affected by both non-conventional correlated function and vortex phase. Our results are verified well by the experiment results.

scholarly journals Controlling the Spatial Coherence of an Optical Source Using a Spatial Filter

2018 ◽  
Vol 8 (9) ◽  
pp. 1465 ◽  
Author(s):  
Milo Hyde
Keyword(s):  
Optical Communications ◽  
Free Space ◽  
Spatial Coherence ◽  
Spatial Filter ◽  
Closed Form Expression ◽  
Free Space Optical ◽  
Filter Function ◽  
Degree Of Coherence ◽  
Spectral Degree ◽  
Directed Energy

This paper presents the theory for controlling the spectral degree of coherence via spatial filtering. Starting with a quasi-homogeneous partially coherent source, the cross-spectral density function of the field at the output of the spatial filter is found by applying Fourier and statistical optics theory. The key relation obtained from this analysis is a closed-form expression for the filter function in terms of the desired output spectral degree of coherence. This theory is verified with Monte Carlo wave-optics simulations of spatial coherence control and beam shaping for potential use in free-space optical communications and directed energy applications. The simulated results are found to be in good agreement with the developed theory. The technique presented in this paper will be useful in applications where coherence control is advantageous, e.g., directed energy, free-space optical communications, remote sensing, medicine, and manufacturing.

Q-switched partially coherent lasers with controllable spatial coherence

2021 ◽  
Vol 51 (2) ◽  
Author(s):  
Yushuang Wang ◽  
Xuanxuan Ji ◽  
Ziyang Chen ◽  
Jixiong Pu
Keyword(s):  
Laser Pulse ◽  
Spatial Coherence ◽  
Transverse Mode ◽  
Spatial Filter ◽  
Laser Resonator ◽  
Coherent Light ◽  
Partially Coherent ◽  
Partially Coherent Light ◽  
Degree Of Coherence ◽  
Output Laser

We develop a Q-switched degenerate laser, delivering a partially coherent light pulse of duration about 16 ns. The spatial coherence of the output laser pulse can be varied by tuning the spatial filter inside the laser resonator, and the oscillating transverse mode structure can be determined by measuring the degree of coherence of the output laser pulse. It is shown that the larger is the diameter of the spatial filter, the more are the oscillating transverse modes, and the lower is the degree of coherence. Based on coherent-mode representation for the partially coherent source, we can estimate the transverse mode contribution to the output partially coherent laser. The experimental results on suppressing speckle demonstrate that the generated partially coherent light possesses the characteristics of rapid reduction of spatial coherence, making it an ideal source for high-speed imaging and ranging applications.

scholarly journals Correlation-induced self-focusing and self-shaping effect of a partially coherent beam

2016 ◽  
Vol 4 ◽  
Author(s):  
Yahong Chen ◽  
Yangjian Cai
Keyword(s):  
Correlation Function ◽  
Intensity Distribution ◽  
High Power ◽  
Thermal Processing ◽  
Coherent Beam ◽  
The Other ◽  
Model Function ◽  
Partially Coherent ◽  
Self Focusing ◽  
Propagation Properties

A new specially correlated partially coherent beam named nonuniform multi-Gaussian correlated (NMGC) partially coherent beam is introduced. The correlation functions of such beam in $x$ and $y$ directions are different from each other, i.e., nonuniform correlation function in one direction and multi-Gaussian correlated Schell-model function in the other direction. The propagation properties of an NMGC partially coherent beam in free pace are demonstrated, and we find that the intensity distribution of such beam exhibits self-focusing and self-shifting effect in one direction and self-shaping effect in the other direction on propagation. The correlation-induced self-focusing and self-shaping effect will be useful in some applications, where the high power and shaped laser is required, such as material thermal processing and laser carving.

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