多层电介质衍射光栅高功率激光辐照特性研究

发布时间：2018-05-28 06:11

本文选题：测量 + 光谱合成　；参考：《中国激光》2017年05期

【摘要】：多层电介质反射式衍射光栅作为光谱合成系统的核心元件,在高功率激光辐照下的表面形变将导致其衍射特性改变,进而影响系统合成光束质量和衍射效率。搭建泰曼-格林干涉仪探测在高功率激光辐照下衍射光栅表面的干涉条纹,经图像处理及泽尼克多项式拟合实现光栅表面形貌的重建。采用高功率光纤激光辐照加热光栅,测量另一光束经过热畸变光栅后的光束质量和衍射效率演变。结果表明,在高功率激光辐照下光栅表面形变高度分布为高斯型,辐照功率密度3kW/cm~2时,干涉条纹对应区域内的光栅表面在垂直方向上隆起,最大高度为127nm。表面形变引起衍射光束质量因子M2退化,这种退化主要来自衍射光远场发散角的增大。光栅衍射效率波动幅度小于1.8%。
[Abstract]:Multilayer dielectric reflective diffraction grating is the core component of the spectral synthesis system. The surface deformation under high power laser irradiation will lead to the change of its diffraction characteristics, which will affect the system synthesis beam quality and diffraction efficiency. A Tyman-Green interferometer was built to detect the interference fringes of the diffraction grating surface under high power laser irradiation. The surface morphology of the grating was reconstructed by image processing and Zehnik polynomial fitting. The beam quality and diffraction efficiency evolution of another beam passing through the thermal distortion grating were measured by heating the grating with high power fiber laser. The results show that the surface deformation height of the grating is Gao Si type under high power laser irradiation. The surface of the grating in the corresponding region of interference fringes is raised in the vertical direction with a maximum height of 127 nm. The radiation power density is 3 kW / cm ~ 2. Surface deformation results in the degradation of the diffractive beam quality factor M2, which is mainly due to the increase of the far field divergence angle of the diffractive light. The diffraction efficiency fluctuation amplitude of grating is less than 1.8.
【作者单位】：中国科学院上海光学精密机械研究所上海市全固态激光器与应用技术重点实验室;中国科学院大学;南京先进激光技术研究院;南京中科神光科技有限公司;
【基金】：国家自然科学基金(U1330134;61308024) 上海市自然科学基金(16ZR1440100;16ZR1440200) 江苏省科技支撑计划(BE2014001) 江苏省重点研发计划(BE2016005-4) 科技部重点专项(2016YFB0402201)
【分类号】：TN24

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