Amplification properties of KW Nd/Cr:YAG ceramic multi-stage active-mirror laser using white-light pump source at high temperatures

An output peak power of over 1 kW for a Nd/Cr3+:YAG ceramic multi-amplifier system with white-light pumping was obtained. A four-stage active-mirror amplifier system was adapted for obtaining kW laser peak power. Output spectrum of pumping light used was close to that of solar light. Enhancement of saturated output laser power at high temperatures was observed owing to the phonon-assisted cross-relaxation effect. An output laser peak power of 1.6 kW were achieved at a ceramic disk temperature of 100 °C. The evaluated optical-optical conversion efficiency for volume of ceramics through which laser passed was 63% for the maximum output laser peak power of 1.6 kW. The laser system will be applicable to solar-pumped lasers with high optical-optical conversion efficiency.