Kerr-lens mode-locked Tm-doped sesquioxide ceramic laser

Kerr-lens mode-locked solid-state laser operation at ∼ 2 µ m is investigated. Using a T m 3 + -doped ( L u , S c ) 2 O 3 “mixed” sesquioxide ceramic as a gain medium, pulses as short as 58 fs are generated at ∼ 2081 n m via soft-aperture Kerr-lens mode locking. The average output power amounts to 220 mW at a pulse repetition rate of 84.8 MHz. The emitted spectrum at the long-wavelength wing extends to > 2.2 µ m which is attributed to vibronic transitions of the T m 3 + ions. The latter is found to be essential for generating pulses with durations in the 50 fs range.