Characteristics of thermal lens induced in active rod of cw Nd:YAG laser

Abstract

The structure of thermal lens induced in active rod of cw Nd: YAG laser was investigated using the Mach-Zehnder interferometer and electronic speckle pattern interferometry (ESPI) system. It is shown that thermal lens has weak aberrations and coincides to the with that of parabolic lens. The se aberrations play role of perturbations and lead to the oscillation of all transversal modes that exceed the threshold of oscillation. It is shown that the change of the pumping level leads to thermal lens displacement and the changes of its principal planes.