Abstract

Various cooling schemes for longitudinally pumped rods as well as temperature, thermal stress and phase error profiles have been intensively studied for the last decade. From results of analytical and numerical studies one can conclude that the lowest thermal stress and center-boundary temperature difference correspond to in-full-face-pumped laser rod. In particular, it is very easy to show analytically (for the case of top-flat shaped heating) that the optimal pump distribution corresponds to the uniform one. Besides, the in-full-face-pump geometry allows to capture the pump light inside the rod owing to internal reflection and increase the rod length in order to relieve thermal load. Thus, the optimal rod geometry may be proposed as follows : laser rod should be a fiber in respect to the pump beam propagation and it should be like a bulk in respect to fundamental mode, with its faces being a sort of natural apertures. It means practically that for a cavity length of several centimeters the diameter of laser rod should be not more than a half of millimeter.

© 2001 EPS