ZnS薄膜在532nm波长激光辐照下的光谱透射及激光损伤特性

Spectral Transmission and Laser Damage Characteristics of ZnS Thin Films Irradiated by Laser at 532 nm Wavelength

为探究ZnS薄膜的激光辐照效应,采用热蒸发沉积技术制备了ZnS薄膜,探究了薄膜在532nm波长激光诱导辐照下,不同能量阶和不同脉冲数对薄膜折射率、消光系数、损伤形貌、表面粗糙度和激光损伤阈值的影响。研究结果表明:ZnS薄膜的平均损伤阈值为1.59J·cm^-2,用平均阈值能量的60%对薄膜进行辐照处理后,可将ZnS薄膜在532nm处的折射率从2.3604提高到2.3849(15脉冲辐照)。用5脉冲辐照薄膜表面后,薄膜的消光系数会随着激光能量的增加而减小。532nm激光辐照下,ZnS薄膜经历了从轻度损伤到极度损伤的缓慢演变阶段。在5脉冲的基础上,增加激光的辐照能量会使薄膜的表面粗糙度Ra下降,最大可由1.52nm下降到0.429nm。

The study aims to examine the effect of laser irradiation on ZnS film.ZnS film was prepared by the thermal vapor deposition technique.With the film irradiated by 532 nm laser,the effects of different energy levels and different numbers of pulses on its refractive index,extinction coefficient,damage morphology,surface roughness and laser damage threshold were investigated.The results show that the average damage threshold of the ZnS film is 1.59 J·cm^-2.After the film is irradiated with 60% of the average threshold energy,the refractive index of the ZnS film at 532 nm can be increased from 2.360 4 to 2.384 9 (15 pulses irradiation).After the film surface is irradiated with 5 pulses,its extinction coefficient decreases with the increase of laser energy.Irradiated by 532 nm laser,ZnS film has experienced a slow evolution from mild damage to extreme damage.On the basis of 5 pulses,increasing laser's irradiation energy reduces the surface roughness R a,from 1.52 to 0.429 nm.