Relatively efficient (up to 3%) third-harmonic generation of picosecond Nd:YAG laser pulses for wavelength λ = 1.06 μm in a low-density laser plasma is reported for a coherent (i.e., collinear) geometry. The third-harmonic beam produced is nearly diffraction limited and coherent and can be used in other nonlinear-optical experiments. A simple theoretical model is proposed in order to explain this result. In the model, third-harmonic generation is considered to be a process that arises from the scattering of electrons by ions in the presence of the strong laser field.
© 1991 Optical Society of America
A. B. Fedotov, S. M. Gladkov, N. I. Koroteev, and A. M. Zheltikov, "Highly efficient frequency tripling of laser radiation in a low-temperature laser-produced gaseous plasma," J. Opt. Soc. Am. B 8, 363-366 (1991)