Efficient frequency conversion of cw mode-locked tunable ps pulses in the visible and near infrared spectral region

Abstract

Generation of ultrashort light pulses tunable in the whole visible and infrared spectral region is of considerable interest for a wide range of applications. Nonlinear frequency mixing techniques are well suited to generate such ultrashort tunable light pulses with a high repetition rate in these wavelength ranges. In particular, second-harmonic, sum, and difference frequency generation allow for the generation of tunable light pulses in a wide wavelength range depending on the laser sources used. Femtosecond pulses, e.g., have been generated in the wavelength range from 1.3 μm to 1.6 μm by difference frequency mixing of the cw mode- locked radiation of a Nd:YAG laser and a dye laser.1,2 In this contribution we report on the generation of tunable picosecond pulses in the wavelength range from 620 nm to 680 nm, 725 nm to 900 nm, and 2.6 μm to 4 μm by frequency conversion processes between the cw mode-locked radiation of a NaCl:OH color center laser and a Nd:YAG laser which is also used as the pump source for the color center laser.