A theoretical analysis is presented for third-harmonic generation (THG) in KDP for type I/ type II angle-detuning scheme of high-intensity laser to produce third harmonic radiation near 0.35μm. The effects of the third-order nonlinear susceptibilities (χ⁽³⁾ ), transverse walk-off and diffraction, especially, the effects of third-order nonlinearity and the phase variations on the frequency conversion have been discussed. A split-step algorithm based on the Fast Fourier Transform and fourth-order Runge-Kutta integrator is used. The results shown that the third-order nonlinear interactions decreases the tripling efficiency, and increases of the modulate strength of the output intensity of 3ω radiation. However, adjusting the angular detuning can compensate effectively the effects of third- order nonlinearity. Furthermore 3ω conversion efficiency will drop with the increase of the degree of phase variations, and the improve 3ω conversion efficiency can suppress the 3ω wave amplitude ripples.

Date Published: 29 December 2005
PDF: 8 pages
Proc. SPIE 6028, ICO20: Lasers and Laser Technologies, 60282A (29 December 2005); doi: 10.1117/12.667343

Published in SPIE Proceedings Vol. 6028:
ICO20: Lasers and Laser Technologies
Y. C. Chen; Dianyuan Fan; Chunqing Gao; Shouhuan Zhou, Editor(s)