Abstract

Neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers have found numerous uses in scientific and industrial applications,¹ However, a problem in using a laser rod of Nd:YAG and other solid-state materials is their susceptibility to thermal distortion. The thermal gradients in a solid-state laser arise principally from cooling, since the heating associated with pumping occurs approximately uniformly throughout the laser material volume. Cooling is achieved by conduction from the material bulk to a surface. Two shapes that satisfy the cooling requirement are the thin rod and thin slab.² The limitations of the rod geometry have led to development of the slab geometry configurations in which the effects of thermal distortion are compensated by the symmetry of thermal gradients in the laser beam path. An implementation of slab geometry is termed the total internal reflection, face-pumped slab laser.³ In the face-pumped slab laser, the slab faces are pumped optically, i.e., illuminated through two opposing slab faces, to obtain the required inversion energy, and simultaneously the same faces are cooled to obtain a 1-D steady thermal state. Generally, these two parallel faces result in parasitic oscillations depleting the stored energy in the slab.

© 1986 Optical Society of America