铽镓石榴石晶体的脉冲激光损伤

Pulsed laser damage of terbium gallium garnet crystals

  • 摘要: 通过泵浦探测超快成像技术,采用固体激光器输出的1064 nm激光对铽镓石榴石(TGG)磁光元件的入射面、出射面进行了辐照损伤测试,研究了铽镓石榴石晶体镀膜元件在基频1064 nm脉冲激光辐照下的损伤特性及损伤后的动力学特性。结果表明,镀膜元件在出射面表现出较低的损伤阈值,而入射面和出射面损伤差异主要受激光诱导的等离子体效应影响。通过超快阴影成像研究发现,铽镓石榴石晶体入射面初始损伤主要来源于膜层杂质缺陷,在高能下会发生膜层的剥离;出射面损伤主要以基底材料中的杂质缺陷诱导损伤为主,损伤坑的尺寸随着激光能量的增加而逐渐增大。

     

    Abstract: This article mainly investigated the incident and exit surfaces of terbium gallium garnet (TGG) magneto-optical elements by damaged by the laser with wavelength of 1064 nm through pump-probe imaging technology. The damage characteristics of terbium gallium garnet elements under fundamental 1064 nm pulsed laser irradiation were studied. The results indicated that the coated TGG element exhibited a lower damage threshold at the incident surface compared with the exit surface, and the difference in damage morphology between the entrance and exit surface was mainly influenced by laser-induced plasma effects. It was found that the initial damage on the TGG incident surface mainly came from impurities and defects in the coatings, and the separation of the film layer under high energy would occur; The exit surface damage of coated TGG components was mainly induced by impurity defects in the substrate material, and the size of damage pits increased gradually under higher laser energy. By analyzing the influence of factors such as laser pulse energy, plasma effect, and material damage response on the laser damage threshold, this study provided important and reference for improving the anti-damage ability of TGG magneto-optical materials under high-power laser irradiation.

     

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