Dual-wavelength femtosecond Tm:LuYO₃ ceramic laser in-band pumped by 1650 nm Er:YAG laser

An in-band pumped dual-wavelength femtosecond Tm:LuYO₃ ceramic laser is demonstrated for the first time, to the best of our knowledge. In the continuous wave (CW) regime, a maximum output power of 1.03 W with a slope efficiency of 28.7% is obtained; the center wavelength can be independently tuned within the range of 1962 nm to 2070 nm using output couplers (OCs) with different transmittance rates. A single-wavelength laser at 2059 nm is achieved with the shortest pulse duration of 313 fs, a maximum average output power of 374 mW, and operating at a repetition rate of 93.13 MHz. Using a 3% OC, dual-wavelength femtosecond pulses at 1950 nm and 2047 nm were simultaneously generated. Furthermore, the phenomenon of wavelength redshift was observed as the pump power was increased. These experimental results indicate that in-band pump technology combined with Tm:LuYO₃ ceramics could be a potential means to reduce the thermal effect and scale the output power and conversion efficiency for 2 μm ultrafast lasers.