Dynamics of a laser with a nonlinear TIR Q switch

Computer simulation and experimental investigations of the dynamics are carried out for a solid state laser with an intracavity nonlinear reflector. The nonlinearity appears upon the internal reflection of radiation from the interface between a transparent dielectric and an absorbing liquid due to a change in the refractive index of the latter upon its heating by a refracted laser wave. Our calculations reveal the dynamics of the reflection coefficient and the power of the laser radiation taking into account the variation of temperature and pressure in the boundary layer of the liquid. The dependences of the lasing parameters on the parameters of the nonlinear reflector and pumping power are studied theoretically and experimentally. It is shown that a Q switch based on the thermal nonlinearity of reflection provides the generation of giant laser pulses whose duration varies from a few hundred nanoseconds to a few nanoseconds. Such a Q switch can be fabricated for any spectral region because it is based on a linear absorber rather than on a saturable absorber. Another advantage of this Q switch is the absence of residual absorption, which is a characteristic feature of all phototropic Q switches.