Efficient High-Peak-Power Wavelength-Switchable Femtosecond Yb:LGGG Laser

A systematic study of the spectral properties and ultrafast lasing characteristics of Yb:(Lu_xGd_1-x)₃Ga₅O₁₂(x = 0.062) (Yb:LGGG) disordered crystal was reported for the first time. The broad fluorescence spectral lines indicate a great potential of Yb:LGGG for tunable and ultrafast laser application. In the lasing experiment, a passively mode-locked Yb:LGGG laser was realized, which generated a maximum average power of 1.3 W with pulse duration of 324 fs at the central wavelength of 1029.6 nm, corresponding to a slope efficiency as high as 41.6%. The pulse energy and peak power were calculated to be 22.4 nJ and 69.2 kW. By optimizing the cavity design, the shortest pulse duration of 188 fs was achieved at the central wavelength of 1026.8 nm. In this case, the maximum average output power of 0.77 W was generated with a slope efficiency of 27.1%. The experimental results show the excellent potential of Yb:LGGG crystal for high-efficiency and high-peak-power femtosecond laser.