Johnson R L, O'Keefe J D
Appl Opt. 1972 Dec 1;11(12):2926-32. doi: 10.1364/AO.11.002926.
A small perturbation model is used to obtain analytical expressions for the critical or runaway power density for laser windows constructed of semiconductor materials. These equations are used to compute the critical power density for several realistic window installations taking account of the finite value of realizable convection cooling coefficients. Computations were prepared for silicon transmitting 4 .0-micro. radiation and for germanium at 10.6 micro. In this way it is shown that power densities are principally limited by the effectiveness of cooling from the face of the window, that is, the surface perpendicular to the laser beam. Since convection cooling coefficients are small the transmission of high power densities through semiconductor windows is therefore contingent upon finding more effective means to cool the window from the face. Finally, a simplified calculation was made in an attempt to account for nonuniformity of the incident laser beam. a given window, but not severely. The results show the onuniformity reduces the runaway power for a given window, but not severely.
使用一个小扰动模型来获得由半导体材料制成的激光窗口的临界或失控功率密度的解析表达式。这些方程用于计算几种实际窗口装置的临界功率密度，其中考虑了可实现的对流冷却系数的有限值。针对传输4.0微米辐射的硅以及10.6微米的锗进行了计算。通过这种方式表明，功率密度主要受窗口表面（即垂直于激光束的表面）冷却效果的限制。由于对流冷却系数较小，因此高功率密度通过半导体窗口的传输取决于找到更有效的从窗口表面冷却的方法。最后，进行了简化计算以尝试考虑入射激光束的不均匀性。对于给定的窗口，这种不均匀性会降低失控功率，但影响不严重。结果表明，不均匀性会降低给定窗口的失控功率，但影响不严重。
