POWER FIBER LASERS;
BRIGHTNESS ENHANCEMENT;
WAVELENGTH CONVERSION;
FREQUENCY-CONVERSION;
D O I:
10.1364/OL.44.002506
中图分类号:
O43 [光学];
学科分类号:
070207 ;
0803 ;
摘要:
An external cavity diamond Raman laser with 1.2 kW output power is demonstrated for durations 7 times longer than the thermal lens time constant. An 83% slope efficiency and a 53% optical-to-optical efficiency were obtained for conversion from a 1.06 mu m pump to the 1.24 mu m first Stokes. The pump had an M-2 of 15, demonstrating that efficiency is maintained at the highest levels even when using exceptionally poor quality pumps. We show that a measured decrease in the output beam quality factor from M-2 = 2.95 to M-2 = 1.25 as power increased is evidence for thermal lens development in the diamond. The results foreshadow development of continuous-wave kilowatt-class lasers or amplifiers based on single diamond elements and pumped efficiently by lasers having poor spatial coherence such as line-narrowed diode laser arrays. (C) 2019 Optical Society of America