Photoacoustic detection of heat generation in proton-implanted Nd:YAG waveguides with and without laser operation

摘要

In this work the heat generation in proton-implanted planar Nd:YAG waveguides with and without laser action is determined by using photoacoustic techniques. From the analysis of the photoacoustic signal in the two emission regimes (stimulated and spontaneous) as a function of the absorbed power, it was found that the heat generated is substantially reduced during laser action. The quotient of the heat generated in both emission channels (stimulated and spontaneous) was found to be S_(stimulated)/S_(spontaneous) = 0.65 +- 0.03. This value is in agreement with the theoretical estimation considering a Nd~(3+) quantum efficiency Φ_(waveguide) = 0.78, extracted from the lifetime measured in the waveguide, slightly lower than the value in the bulk. This work demonstrates that photoacoustic measurements provide a sensitive method to characterize the performance of waveguide lasers.