Allen S D, Rudisill J E
Appl Opt. 1977 Nov 1;16(11):2914-8. doi: 10.1364/AO.16.002914.
Laser calorimetry was used to measure the optical absorption of several candidate window materials for application at CO laser wavelengths. These materials include KCl, CaF(2), SrF(2), and ZnSe. The long, thin bar technique was used to separate bulk and surface absorption contributions by means of their time dependencies. One sample of KCl, known to be low absorbing at 10.6 microm, exhibited no measurable absorption within the sensitivity of the calorimeter (beta(t) < 2 x 10(-6) cm(-1)). The absorption coefficients measured for two samples of CaF(2) at 5.41 microm were higher than those measured by other investigators at 5.25 microm, but, when fitted to an exponential dependence on wavelength, compared favorably with currently measured values. To compare results from different laboratories, precise definition of the spectral power distribution is essential. The surface absorption was, in all cases, small relative to similar measurements at 10.6 microm; in several cases it was not separable from bulk absorption by the technique used.
采用激光量热法测量了几种适用于CO激光波长的候选窗口材料的光吸收。这些材料包括KCl、CaF₂、SrF₂和ZnSe。使用细长棒技术通过时间依赖性来分离体吸收和表面吸收贡献。已知在10.6微米处吸收较低的一个KCl样品，在量热计的灵敏度范围内未表现出可测量的吸收（β(t) < 2×10⁻⁶ cm⁻¹）。在5.41微米处测量的两个CaF₂样品的吸收系数高于其他研究人员在5.25微米处测量的吸收系数，但是，当拟合为对波长的指数依赖性时，与当前测量值相比具有优势。为了比较不同实验室的结果，光谱功率分布的精确定义至关重要。在所有情况下，表面吸收相对于在10.6微米处的类似测量都较小；在几种情况下，通过所使用的技术无法将其与体吸收区分开来。
