EFFECT OF PUMPING TYPES ON OPTICAL PATH DIFFERENCE IN ND:YAG LASER ROD

Abstract

The finite element method has been used successfully to determine the temperature distribution throughout Nd:YAG laser rod subjected to one end power pumping cooled by water from the longitudinal side. Displacement, strain and stress are obtained numerically depending on the temperature distribution using Hook’s law. The influence of two types of pumping methods on temperature, displacement, strain and stress is obtained. The optical path difference is obtained  and compared with a previously published experimental data and a good agreement has been found. Some conclusions are drawn; Gaussian beam pumping causes higher temperature distribution more than Top hat beam pumping at and near the center of the rod, which may cause higher optical path difference there. Even Top hat beam pumping causes some high tensile hoop stress, it may be a better choice while designing laser system since it results in low optical path difference