Repetitive Pulse Performance of One-Micrometer Laser-Ablation Propulsion onto Aluminum

The impulse characteristics of an aluminum ablator against repetitive Nd:YLF laser pulses with a 1047 nm wavelength and 5 to 15 ns pulsewidth were investigated. The laser was operated in burst mode varying the pulse repetition frequency, single-pulse energy, and number of pulses in a burst. The burst was repeated until the impulse reached saturation. A torsion pendulum was used to measure the total impulse generated in a single burst with an accuracy higher than 2%, even with a 1 s burst period. The impulse increased, and then it gradually reached saturation as the total laser energy increased. In the operation range examined, the saturation value of the impulse increased with increasing single-pulse fluence.