Thermal lens measurement of a LD end-pumped Nd:GdVO_4 laser with stable resonator by a slit-scanning method

摘要

A simply method to measure the thermal focal length of a LD end-pumped Nd:GdVO_4 solid state laser with a stable resonator is presented. By scanning a slit across the field with expression of multi-mode Gaussian distribution behind the output mirror of lasers, the radius and the M~2 factor describing the quality of beam can be measured. The waists of the multi-mode field and the TEM_(00) mode can be deduced according to the law of multi-mode Gassian beam propagation. Based on the ABCD matrix theory of a stable resonator, the thermal focal length of the active medium can be easily obtained. The thermal focal length of a LD end-pumped Nd: GdVO_4 laser has been measured and the experimental results agree with the theoretically analyzed values.