Pyrromethene-doped xerogels for solid state dye laser systems

Abstract

During recent years, much research has been devoted to the improvement of dye doped solid state materials for pulsed laser applications. We report results obtained with hybrid materials doped with many different dyes and synthesized by using the sol-gel process. The best and very promising results were obtained with the pyrromethenes and are the following: We used a linear stable cavity longitudinally pumped by a nanosecond frequency-doubled Nd:YAG laser. Conversion efficiencies of 70% were obtained with no saturation effect, at least up to 15 mJ/pulse pump energy. Output emission in excess of 10 mJ were thus obtained. We monitored the evolution of the output energy when operating the solid state dye laser at about a millijoule energy pumping level, always using the same area of the sample. The progressive dye degradation leads to a decrease of the output energy. However, we may obtain high lifetime at high repetition rate: over 500,000 pulses may be emitted at 20 Hz by the same area of the sample, before the output energy decreases to half of its initial value. Moving the sample allows us to achieve with one sample, a very stable laser emission of about one millijoule for over one month utilization. This opens the route towards routine use of such solid state dye laser systems. Yet, we are still improving the stability of the dye incorporated in the solid matrices, in particular by studying the effect of removing the oxygen from the samples