Subpicosecond neodymium laser with a contrast ratio in excess of 1012

Stimulated Raman scattering of mode-locked ruby laser radiation in SF₆ and hydrogen was used to generate pulses of 0.5 ps duration and of 0.1 mJ energy at the wavelength of 1.056 μm. Amplification of the pulses in a single-pass (12 cm long) neodymium phosphate glass amplifier increased the energy to 0.5 mJ and the measured contrast ratio of the pulses exceeded 10¹².