THERMAL ANALYSIS OF LD PUMPED ND:Yag LASER SLAB AND FAILURE ANALYSIS

Abstract

As part of the R&D effort conducted within the Laser Laboratory of the European Space Agency, various simulation tools are being developed to understand and correct the thermal effects of side pumping an Nd:YAG slab with multiple individual High Power Laser Diodes. The scope of the present activity, which complements the work reported elsewhere at this workshop, is to emulate the thermal effects of a real amplifier and study the effects of various combinations of laser diode stacks with different characteristics, such as operational wavelength, temperature of operation, transmitted energy and pumping efficiency on the dynamic temperature distribution inside the slab. The motivation of this analysis is to work towards a simplification of the phenomena of heat generation and convection inside the crystal which account for the thermal lensing effect. Transient analysis is performed at different pump intensities under variable boundary conditions and the results are compared with experimental data as well as other software such as Zemax and LASCAD. Also the effects of laser diode stack failures are investigated and reported. The algorithm developed is based on the finite element method using tetrahedral elements for the adjustable meshing.

As part of the R&D effort conducted within the Laser Laboratory of the European Space Agency, various simulation tools are being developed to understand and correct the thermal effects of side pumping an Nd:YAG slab with multiple individual High Power Laser Diodes. The scope of the present activity, which complements the work reported elsewhere at this workshop, is to emulate the thermal effects of a real amplifier and study the effects of various combinations of laser diode stacks with different characteristics, such as operational wavelength, temperature of operation, transmitted energy and pumping efficiency on the dynamic temperature distribution inside the slab. The motivation of this analysis is to work towards a simplification of the phenomena of heat generation and convection inside the crystal which account for the thermal lensing effect. Transient analysis is performed at different pump intensities under variable boundary conditions and the results are compared with experimental data as well as other software such as Zemax and LASCAD. Also the effects of laser diode stack failures are investigated and reported. The algorithm developed is based on the finite element method using tetrahedral elements for the adjustable meshing.