Nonlinearly coupled, gain-switched Nd:YAG second harmonic laser with variable pulse width

Abstract

An all-solid-state, gain-switched, green laser is developed using a side diode-array pumped Nd:YAG laser and a KTiOPO(4) (KTP) crystal as an intracavity frequency doubler. The effect of nonlinear coupling on the pulse width of the fundamental is studied and is found to be in good agreement with the experimental measurement. In this preliminary experiment, a peak power of 40 W at 532 nm corresponding to a pulse width of 409 ns is obtained for an average pump power of 2 W. Compared to a Q-switched laser, it is simple and does not require a high voltage RF driver or saturable absorbers in its operation. The laser may be useful where relatively longer nanosecond pulses are required such as eye surgery, micromachining, and underwater communication.

Gain broadening and mode-locking in overcoupled second harmonic Q-switched microsecond pulses

“…In this so called overcoupling regime the pulse energy only decreases slightly with increasing conversion efficiency while the pulse duration increases significantly. Thus the overcoupling effect provides a method to adjust the pulse duration without significant loss of energy [11][12][13]. Generation of microsecond pulses with durations of 3.2 μs at 3.4 mJ by utilizing this technique has been demonstrated at a wavelength of 527 nm [11].…”