Watt-level broadly wavelength tunable mode-locked solid-state laser in the 2 μm water absorption region

We report on broadly wavelength-tunable passive mode-locking with high power operating at the 2 mu m water absorption band in a Tm: CYA crystal laser. With a simple quartz plate, stable mode-locking wavelengths can be tuned from 1874 to 1973 nm, with a tunable wavelength range up to similar to 100 nm and maximum output power up to 1.35 W. The bandwidth is narrow as similar to 6 GHz,corresponding to a high coherence. To our knowledge, this is the first demonstration of wavelength-tunable mode-locking with watt-level in the 2 mu m water absorption band. The high temporal coherent laser can be further applied in spectroscopy, the efficient excitation of molecules, sensing, and quantum optics. (C) 2017 Chinese Laser Press