Abstract

The formation of gratings accompanying a population grating in a flash-lamp pumped Nd:YAG laser amplifier has been studied by using both nondegenerate and degenerate four-wave mixing techniques. In our investigations the grating of population inversion was induced by optical waves at 1064 nm. The refractive index grating caused by the population grating was read by an optical wave at another wavelength (1054 nm or 694 nm) in nondegenerate four-wave mixing experiments. In the degenerate four-wave mixing experiments the total grating, i.e. the sum of the refractive index and gain gratings, was read by resonant wave (at 1064 nm wavelength). The dependence of the ratio of real and imaginary parts of the resonant susceptibility of Nd:YAG at 1064 nm on the pump power has been determined through comparison of experimental results and numerical calculations.

© 1998 Optical Society of America