Light-gasdynamic-induced refractive index changes and beam propagation in fast-pumped high-power photodissociation lasers.

In high-power photodissociation lasers such as the iodine laser, spatially inhomogeneous pump light deposition causes temperature and pressure gradients. These gradients set the gaseous laser medium into motion, thereby changing its density and thus also its refractive index. These perturbations may seriously degrade the laser beam quality. A pulse propagation model is presented, which for the first time incorporates the gasdynamic disturbances in an appropriate manner. Thus any deterioration of the beam quality resulting from gasdynamic effects and diffraction can be precisely evaluated. The model is shown to compare well with experiment. It is also suited for predicting the performance of high-power amplifier chains. [ABSTRACT FROM AUTHOR]