A Nd:YAG crystal having a special structure achieved laser operation with an extinction ratio of over 20 dB, a CW (continuous wave) average power of 6 W, a pulse width of 50 ns, and repetition rates in the range 1 kHz - 10 kHz for an output wavelength of 1064 nm for effectively cooling the crystal for the case of laser dressing. The birefringence induced by the stress applied to the crystal results in the production of elliptical polarization before the Brewster-window and thus decreases the laser efficiency. In this paper, we analyzed the relationship between the distortion and the birefringence in a Nd:YAG crystal and the resulting effect on the laser power.