Physical optics modelling of intra-cavity thermal distortions in solid state laser resonators

摘要

Laser resonators are very sensitive to intra-cavity losses and instabilities. When high power extraction is required, thermal distortions introduced from pumping the active medium cause the resonator to become unstable. We model these effects, and find a closed form solution to the wavefront change, as a function of time. Using physical optics modelling methods, we show that diffractive effects are needed to explain the onset of optical damage, and derive an analytical equation that describes the compensation of the resonator instabilities in real time for damage minimisation.