Continuously tunable deep-red laser based on Pr3+:YLF

A mechanism of assembling the multi-metastable levels as a composite-metastable level was proposed, enabling wide tuned emission as large as a few ten nanometers, and breaking the restriction of less than 1 nm continuous tuning for Pr3+:YLF crystals in the deep-red region. To the best of our knowledge, a deep-red continuous wave laser with a continuously tunable range of more than 30 nm (685.1 nm to 715.8 nm) in Pr3+:YLF was realized for the first time, by using a 24 W InGaN laser diode array at 444 nm. The total tuning range is from 685.1 to 721.4 nm. The output power range from 0.24 W up to 5.01 W was achieved. The maximum output power of 5.01 W was obtained at 720.9 nm, with a slope efficiency of 44%. The Mz and My2 factors were measured to be 2.78 (x) and 2.55 (y) at 720.9 nm, with the power fluctuations within 4%.

Automated summary

A mechanism was proposed to assemble multi-metastable levels into a composite-metastable level, enabling wide tuned emission of several tens of nanometers in Pr3+:YLF crystals. The study achieved, for the first time, a deep-red continuous wave laser with a tunable range exceeding 30 nm (685.1 nm to 715.8 nm) in Pr3+:YLF, using a 24 W InGaN laser diode array at 444 nm. The output power ranged from 0.24 W to 5.01 W, with a maximum power of 5.01 W achieved at 720.9 nm and a slope efficiency of 44%.