Operation of the continuously pumped, repetitive Q-switched YAlG:Nd laser

The continuously pumped YA1G : Nd laser has been repetitively
Q
-switched by a rotating mirror, yielding pulses with a peak power of 1 kW, a pulse width of 175 ns, and a repetition rate of 500 pulses per second. The output, at a wavelength of 1.064 microns, consisted of five longitudinal modes with approximately 60 percent of the power in the lowest order TEM
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transverse mode. The dependance of the laser performance on mirror curvature and transmission. was studied, and the system was optimized with respect to peak power and pulse amplitude stability. The observed performance is compared to theory and found to be in excellent agreement. Consideration is given to the possibility of achieving higher peak powers and shorter pulse widths, with the conclusion that pulse widths of 75 ns and peak powers of 200 kW should be possible with continuous tungsten pumping by using 6.25 mm diameter 7.5 cm long rods, Repetition rates approaching 4000 Hz with full peak power and higher rates at reduced peak power levels are possible. Results of flash lamp pumping experiments indicate that with the same crystal used here peak powers of 1MW and pulse widths of 5 ns or less are possible using a flash lamp input of approximately 10 watts. seconds. Several applications of this laser including the field of nonlinear optics are considered. The most promising application at present appears to be in the field of micromachining, where the feasibility of fabricating passive thin film circuitry has been established.