Laser pulse dynamics in a repetitively pump-pulsed Nd:YAG laser are examined. Analytic expressions for the laser pulse height and pulse width for a pump-pulsed laser are given, and the variation of the pulse height and width with pump power, cavity length, and cavity loss in the pump-pulsed mode is compared to the variation in the Q-switched mode. By pulsing a xenon pump lamp (with the lamp discharge maintained at a subthreshold value between pulses), 200 W, 200 nsec laser pulses were generated at repetition rates of several hundred per second. The predicted variation of the laser pulse height, width, and delay with pulsed pump power was verified. Using currently available YAG material and pump cavities, it is shown that 3600 W, 200 nsec laser pulses should be available at 50 kW pulsed pump powers.

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X-ray diffraction from piezoelectrically amplified acoustic shear waves in GaAs is reported. The spectrum of amplified acoustic flux is obtained in the microscopic limit, where the electron mean free path is much greater than the acoustic wavelength. The peak acoustic intensity occurs at 50 GHz, which corresponds to the frequency of maximum net gain according to the linear theory. The spectrum of piezoelectrically amplified acoustic waves is observed at frequencies an order of magnitude larger than may be studied by the previously reported Brillouin scattering technique.