# 夹杂物和气泡的均匀性和散射

This is Sections 1.6 and 1.7 of the Laser Optics Resource Guide.

### 均匀性

(1)$$\Delta s= d \times \Delta n$$

∆s is the wavefront deviation, d is the substrate thickness, and ∆n is the P-V variation in refractive index. A high degree of homogeneity, or rather, a low degree of variation, is especially important for applications with high-powered lasers. 材料熔化的过程会使均匀性发生变化。混合不当和热力学不平衡导致密度变化，冷却和退火过程可能导致应变波形。非均匀性采取全局不均匀性（即整块玻璃的折射率变化）或条纹的形式，这是覆盖大约0.1mm 到 2mm 的玻璃的局部均匀性。表 1 所示定义一般均匀性分类的最大折射率变化。

 SCHOTT 均匀性分类 ISO 10110 第 4 部分 均匀性分类 根据 ISO 10110 第 4 部分，折射率的最大变化 根据 ISO 12123 和SCHOTT 光学玻璃目录，折射率的最大变化 S0 0 ±50 × 10-6 - S1 1 ±20 × 10-6 - H1 1 ±20 × 10-6 40 × 10-6 H2 2 ±5 × 10-6 10 × 10-6 H3 3 ±2 × 10-6 4 × 10-6 H4 4 ±1 × 10-6 2 × 10-6 H5 5 ±0.5 × 10-6 1 × 10-6

##### 图 1: 比较均匀透镜与 GRIN 透镜将光聚集到点

Non-homogeneity causes scattering, which degrades system performance and could lead to laser induced damage from high-power lasers. To prevent damage, as well as efficiently use energy, it is important for transmissive laser optics to be highly homogenous and thereby avoid deformation of the transmitted wavefront and polarizing transmission effects.

### 杂质和气泡造成的散射

 标准 VB EVB 每 100cm3 玻璃的的最大横截面 (mm2) 0.03 0.02 0.006 每 100cm3 体积 (cm3) 的 10 4 2 标准 VB EVB 最大数量 (cm3) 单个气泡允许的最大直径 (mm) 800 0.55 0.45 0.25 500 0.44 0.36 0.20 300 0.34 0.28 0.15 200 0.28 0.23 0.12 100 0.20 0.16 0.09 50 0.14 0.11 0.06
##### 表 2: 光学介质中的气泡和夹杂物的分类3

1. F. Reitmayer and E. Schuster, "Homogeneity of Optical Glasses," Appl. Opt. 11, 1107-1111 (1972)
2. “TIE-26: Homogeneity of Optical Glass.” Schott, February 2016.
3. “TIE-28: Bubbles and Inclusions in Optical Glass.” Schott, May 2016.

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