固体介质间隔层激光标准具性能的影响因素研究

针对固体介质间隔层的镀膜标准具, 以1 064 nm激光镀膜标准具为例, 首先研究了反射膜堆数对反射带宽、基底厚度以及对自由光谱区的影响:标准具的带宽随着膜层堆数增加而减小, 自由光谱区随着基板厚度的增加而减小;其次研究了基底误差对标准具中心波长定位和透过率的影响, 通过定量数值计算证明了基底误差可通过标准具的使用角度补偿;针对典型的H(LH)^m/Substrate/(HL)^mH和L(LH)^m/Substrate/(HL)^mL两个膜系结构, 研究了入射激光发散角对标准具中心波长偏移、通带半宽度、中心波长透过率和最大透过率的影响。随着激光发散角的增加, 中心波长向短波方向移动, 通带半宽度、中心波长透过率和最大透过率呈现下降的趋势, 并且第二个膜系结构的标准具性能优于第一个膜系结构的标准具。     

Detection of subsurface defects of fused silica optics by confocal scattering microscopy

<正>A non-destructive technique for subsurface measurements is proposed by combining light scattering method with laser confocal scanning tomography.The depth and distribution of subsurface defect layers are represented in term of scattered light intensity pattern,and three types of fused silica specimens are fabricated by different grinding and polishing processes to verify the validity and effectiveness.By using the direct measurement method with such technique,micron-scale cracks and scratches can be easily distinguished,and the instructional subsurface defect depths of 55,15,and 4μm are given in real time allowing for an in-process observation and detection.     

Design and preparation of multilayer optical coatings for laser crystal Nd：YVO4 and KTP

Design and preparation of multilayer optical coatings are investigated on laser crystal Nd：YVO4, YVO4, and frequency doubling crystal KTP substrate. Multilayer optical coatings are deposited on one surface of the crystals using the ion beam sputtering technique, and the other surface is coated with a single SiO2 as protective layer. For the YVO4 crystal after coating, the reflectivity at 1 064 and 532 nm are greater than 99.9% and 99.8%, respectively, and the transmissivity at 808 nm is greater than 91.5%. For the KTP crystal after coating, the reflectivity at 1064 nm is greater than 99.95%, and the transmissivity at 532 nm is greater than 99.5%. After thermal annealing, the transmissivity can be improved. The obtained coated crystals can be used in high Dower solid-state lasers.     

光学薄膜特性的锥角效应数值分析

建立非平行光入射多层膜的模型,给出了在圆形光束锥角入射时的薄膜特性表达式,对三类典型光学薄膜即多腔滤光片、非偏振分光薄膜和非偏振截止滤光薄膜的特性进行了数值实验。研究结果表明:随着光束入射锥角的增加,多腔滤光片的影响是中心波长向短波方向移动,透射率下降和通带形状退化;非偏振分光薄膜的s和p偏振透射率增加,宽带波纹度增加;非偏振截止滤光薄膜的通带透射率出现周期振荡,s偏振的通带波纹度大于p偏振,通带波纹度总体具有增加的趋势,过渡区的陡度具有变大的趋势。     

基于时间控厚离子束溅射技术的宽带减反膜制备

 为了制备满足设计要求的宽角度、宽波段减反膜,利用离子束溅射沉积技术,在时间-功率控厚的模式下,对膜层沉积速率进行了精确修正。在实验中,利用时间-功率控厚的离子束溅射沉积技术,选择HfO₂和SiO₂作为高低折射率组合,在超抛ZF6玻璃基底上制备了宽角度、宽带减反膜,通过对实验后的透过率光谱曲线的数值反演计算,获得膜层厚度修正系数,初步得到了沉积速率随沉积时间变化的规律。利用修正后的沉积参数制备设计的膜系,在0°~30°入射角度下,600~1 200 nm波段的平均透过率达到99%以上。     

金属氧化物薄膜光学常数计算物理模型应用研究

采用离子束溅射(IBS)方法制备了HfO₂和Ta₂O₅两种金属氧化物薄膜,通过测量薄膜的椭偏参数,使用非线性最小二乘法反演计算获得薄膜的光学常数。 在拟合过程中,采用L₈(27)正交表设计了8组反演计算实验,在初始选定Cauchy模型后,对HfO₂薄膜拟合影响最大的为表面层模型,对Ta₂O₅薄膜拟合影响最大的为折射率梯度模型。 确定了不同物理模型对拟合函数MSE的影响权重和拟合过程中模型选择的次序,按照确定的模型选择次序拟合,最后加入弱吸收模型反演计算两种薄膜的光学常数,反演计算的MSE相对初始MSE可下降79%和39%,表明拟合过程模型选择物理意义明确,具有广泛的应用价值。 在500 nm处,Ta₂O₅薄膜的折射率梯度大于HfO₂薄膜, 而HfO₂薄膜消光系数大于Ta₂O₅薄膜。 表明Hf金属与Ta金属相比容易氧化形成稳定的氧化物,HfO₂薄膜的吸收要高于Ta₂O₅薄膜。     

Effect of high-temperature ablation on protective coating of ZnS optical windows

While infrared （IR） hard protective film of ZnS optical window is used in high temperature environment, its optical and mechanical stabilities are the premise of the IR optical system. IR hard protective film is deposited on ZnS optical windows by chemical vapor deposition （CVD）, and ablation experiments are done to the maximum temperature the film can endure. The effects of ablation temperature on the optical and mechanical properties of the protective films are investigated by surface profiler, Fourier-transform infrared （FTIR） spectrometry, IR ellipsometer, and Metallographic microscope. It is shown that the optical and mechanical properties of ZnS hard protective film change little before 500 ℃, and film refractive index and optical thickness reduce while ablation temperature surpassing 500 ℃, forming crater-like ablation structure, which leads to the reduction of film combination significantly.     

Study on optical anisotropy properties of SiO2 films with different thermal annealing temperatures

SiO2 films are deposited on Si substrates by an ion beam sputtering technique and continuously annealed in a quartz culture dish in air at various annealing temperature ranging from 20 to 750 ℃ with a step of 100 ℃ for a fixed time of 24 h. The effects of thermal treatment on optical anisotropy properties of SiO2 films are investigated by spectroscopic ellipsometry. When the annealing temperature is 550℃, the optical anisotropy properties of SiO2 film is minimum. The obtained results indicate that the optical anisotropy properties of SiO2 films can be improved by a proper thermal annealing process.