激光辐射下光学玻璃应力破坏的阈值理论(英文)

Theoretical study on damage thresholds for elastic stress fracture in laser-irradiated optical glass

基于热弹理论,建立了计算光学材料激光诱导破坏阈值的解析模型。特别研究了能量阈值与激光光斑大小以及光学材料力学边界条件的依赖关系。研究表明:在材料响应情形下,光斑效应体现在光斑能量向外的弥散,而在结构响应情形下,不同的边界条件导致不同的破坏阈值与光斑直径之间的函数关系。提出了一种最优边界,使激光诱导产生的拉应力场最小。

Based on thermo-elastic theory, an analytic model is developed for determining the laser fluence required to damage a series of thin glass disks which serve as transmissive optical components. In particular, the dependence of threshold fluence on laser beam diameter and mechanical boundary conditions of samples is investigated. Study shows that beam diameter effect in material response results from the energy loss of the irradiated area. As for structural response, different mechanical boundaries result in different relationships of LIDT(laser induced damage threshold) with radius of laser beam. It is also found that mechanical boundaries have great influence on LIDT even if beam diameter is fixed, and optimal boundary under which tensile stress is eliminated is available theoretically when particular compressive boundary is applied.