RESUMO
We show that thermally induced birefringence in an electro-optical crystal can play an important role in Q-switched Nd:YAG lasers with a high average power output. A compensation of the thermal effects in both active-element and electro-optical crystals is achieved by employing two identical Pockels cells instead of one, with a pi/2 polarization rotator between them in the so-called ring modulator. Experiments that are carried out show that undesirable thermopolarization effects are essentially eliminated by using this new optical configuration. A detailed description in terms of Jones matrices of the properties of the proposed resonator is also included.
RESUMO
In this paper we report on the results of comparative investigations of different pump cavities. Numerical estimations of the geometrical transfer efficiency of various cavities are presented. An experimental study of the pumping efficiency and pumping uniformity of the laser heads with respect to the cavity geometry, types of flashlamp, and reflecting coatings have been carried out. The influence of the discharge circuit on the pumping efficiency is also discussed.