Mode locked solid-state laser pumped by a non-diffraction-limited pumping source and method for generating pulsed laser radiation by pumping with a non-diffraction-limited pumping beam

摘要

A pulsed solid-state laser comprises an optical resonator and a solid-state laser medium placed inside the optical resonator. A saturable absorber, such as a semiconductor saturable absorber mirror device for passive mode locking is placed inside the optical resonator, and a pumping source is provided for exciting the laser gain medium to emit electromagnetic radiation. The pumping source emits pump radiation which impinges on the laser gain medium in the form of a non-diffraction-limited focused pumping beam. The product of the stimulated emission cross section times the spontaneous fluorescence lifetime is low for the laser medium, e.g., 0.1x10-23 cm2s for Ti:sapphire; nevertheless, the laser yields a high output power of a few Watt even if pumped with a non-diffraction-limited pumping beam. Pumping with a non-diffraction-limited pumping beam makes feasible solid-state lasers with remarkably smaller sizes and lower costs, but with the same performance as known lasers.