关键词: 激光器, 固体激光器, 有限元法, 接触热导, 波前畸变

Abstract:

For the LD end-pumped solid-state laser working with round-rod material, the crystal rod is held and cooled by the metal heat sinks. The non-axisymmetric assembly pressure on the side-face of the crystal rod makes the thermal contact conductance between the crystal and the heat-sink non-axisymmetric, which affects the spatial distribution of the temperature inside the crystal rod and the spatial distribution of wavefront. Based on the truncated-Gaussian model and the plastic-deformation model, the model of the thermal contact conductance is established. For the Gaussian heat consumption, the changes of the end-face temperature of the crystal and the wavefront distortion with the radius and the direction angle under different assembly forces are obtained, and the results are compared with those of the case when using the indium foil as thermal interface material. The results show that in the case of the same radius the end-face temperature and the wavefront distortion reach the minimum in the direction of bottom of the heat-sink groove, and reach the maximum in the direction of the contact area of the heat-sink couple. With the increasing assembly force, the end-face temperature reduces overall, and the wavefront distortion gets more uniform. With the indium foil as thermal interface material, the end-face temperature and the wavefront distortion decrease overall. And the the spatial distribution of the temperature of the crystal rod and the wavefront distortion is axisymmetric.

Key words: lasers, solid state laser, finite element method, thermal contact conductance, wavefront distortion