Third-harmonic and three-wave sum-frequency light generation in an elliptical-core optical fiber.

Third-harmonic generation and three-wave sum-frequency light generation in a short-length elliptical-core optical fiber pumped by pulses from a Q-switched and mode-locked Nd:YAG laser, operating at 1.064microm, have been observed in the 355-385-nm spectral range. In particular, the third harmonics of the pump (lambda(0) = 1.064; microm, lambda(0)/3 = 354.7 nm) and of the first Raman Stokes (lambda(1) = 1.116microm, lambda(0)/3 = 372.0 nm) lines have been obtained with 5-kW peak power of the laser pulses.