The line broadening and red shift satellite line phenomena in 1000 GW Nd3+:Phosphate-glass laser system

Using a grating spectrograph with a 0. 006nm resolution to monitor the laser spectrum of ai 1000 GM Nd phosphate-glass laser system. When the laser power intensity is up to 1 GW / cm (100 ps pulse), the laser linewidth has a 1. 04nm broadening, and there is a red-shift(3. 77nm away from the main laser line)satellite line appears. The red shift line consists of several peaks, and spectral intensity is nearly 3 / 5 of the main laser line intensity. When laser power intensity is reduced to 0. 37 J/ cm (3 ns pulses), the red shift phenomena disppears, and line width broadening is less too. The red shift phenomena probably comes from the Raman scattering of the phosphate glass and has been amplified in the gain medium.