Analysis of Scaling Laws for Phase Compensation of Focused Beam under Thermal Blooming Conditions

Pengfei, 张鹏飞 Zhang; Chengyu, 范承玉 Fan; Chunhong, 乔春红 Qiao; Huimin, 马慧敏 Ma; Jinghui, 张京会 Zhang; Haitao, 王海涛 Wang; Yingjian, 王英俭 Wang

doi:10.3788/cjl201239.0213002

Cited by 2 publications

(1 citation statement)

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“…激光通过湍流大气之后就会产生光强起伏、光束漂移、光束扩展和到达角起伏等现象，使光束质量严重退化 [1] ，影响激光的作用效果。因此需要通过镜面形变来改变入射波前的相位,从而改善光束质量 [2] 。控制变形镜 (DM)来校正畸变波前的算法很多，从传统的带波前传感器的校正算法到无波前传感器畸变校正方法，国内外许多学者对此做了大量研究。近些年主要对无波前传感器成像自适应光学系统的畸变校正方法进行研究，从早期利用爬山法、多元高频振动法进行控制参数优化，到现在常用的随机并行梯度下降算法 [3] 、模拟退火和遗传算法 [4] 等并行优化算法对波前进行校正，但是这些算法受限于较低的 CCD 采样频率，仅能校正静态或缓慢变化的畸变。直接斜率法 [5] 取得了很好的效果，通常可以用于时间性能要求较高的场合。本文首先用 21 阶 Zernike 多项式描述的一个畸变波前 [6] ，对畸变波前进行仿真探测，得到波前斜率，通过变形镜变形函数 [7] ，采用直接斜率法，可以求解出加在各个驱动器上的电压值，对变形镜进行控制，从而达到校正畸变波前的目的 [8]…”

Section: 引言unclassified

Correction of Distorted Wavefront Based on Direct Wavefront Gradient Algorithm

Zeshuai¹,

Yi²,

Weihua³

et al. 2014

激光与光电子学进展

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Direct wavefront gradient algorithm directly establishes correspondence between measurands of the wavefront sensor and response characteristics of the deformable mirror. The voltage can be directly calculated by the algorithm. We use Hartmann wavefront sensor with 64 sub-apertures to detect the distorted wavefront. Based on the hypothesis that of deformable mirror is the weighted addition of the influence function, each of the voltage values applied on the drive is solved by the algorithm. The simulated 32 units of deformable mirror can be controlled and then distorted wavefront can be restored. The simulation result shows that direct wavefront gradient algorithm can effectively adjust the distorted wavefronts.

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Section: 引言unclassified

Correction of Distorted Wavefront Based on Direct Wavefront Gradient Algorithm

Zeshuai¹,

Yi²,

Weihua³

et al. 2014

激光与光电子学进展

View full text Add to dashboard Cite

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Analysis of beam deviation induced by thermal blooming effect when high-energy laser propagating up in atmosphere

Zhang¹,

Zhang²,

Su³

et al. 2021

Acta Phys. Sin.

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Based on the thermal blooming effect theory for high-energy laser propagating in atmosphere, the vector model concept of thermal distortion parameter <inline-formula><tex-math id="M1">\begin{document}$ {{\boldsymbol{N}}_{\text{D}}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20211138_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20211138_M1.png"/></alternatives></inline-formula> is put forward. Based on the vector model concept of thermal distortion parameter and the laser system simulation software EasyLaser, the scaling law between the centroid offset of laser beam farfield and the vector thermal distortion parameter is simulated and analyzed. The simulation results indicate that the centroid offset quantity is in direct proportion to the modulus of vector thermal distortion parameter <inline-formula><tex-math id="M2">\begin{document}$ {{\boldsymbol{N}}_{\text{D}}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20211138_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20211138_M2.png"/></alternatives></inline-formula>, and the centroid offset direction is opposite to the direction of vector thermal distortion parameter <inline-formula><tex-math id="M3">\begin{document}$ {{\boldsymbol{N}}_{\text{D}}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20211138_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20211138_M3.png"/></alternatives></inline-formula>. Based on the scaling law, by real-time measuring the atmosphreic parameters on laser beam propagation path, the beam deviation of laser system can be conveniently estimated in practical application.

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Analysis of Scaling Laws for Phase Compensation of Focused Beam under Thermal Blooming Conditions

Cited by 2 publications

References 0 publications

Correction of Distorted Wavefront Based on Direct Wavefront Gradient Algorithm

Correction of Distorted Wavefront Based on Direct Wavefront Gradient Algorithm

Analysis of beam deviation induced by thermal blooming effect when high-energy laser propagating up in atmosphere

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