Sub-100-fs Kerr lens mode-locked Yb:Lu₂O₃ thin-disk laser oscillator operating at 21 W average power

Investigation of crystal field effects for the spectral broadening of Yb3+-doped LuxY2−xO3 sesquioxide crystals

“…The 4f 13 shell electrons of Yb 3+ ion split into two manifolds under the crystal eld effect when the Yb 3+ ion is doped into the sesquioxide crystals: the ground state 2 F 7/2 with four Stark splitting energy levels, and the excited state 2 F 5/2 with three Stark splitting energy levels. 32 The seven energy levels of each component of the Yb:Lu x Y 2Àx O 3 (x ¼ 0, 0.79, 0.99, 1.19, 1.39, and 2) crystals were derived according to the peak positions of the experimental uorescence and absorption spectra.…”

“…[10][11][12] The Yb:Lu 2 O 3 thindisk laser (TDL) generated a pulse width of 96 fs with the highest average output power of 21.1 W in the sub-100 fs regime. 13 However, the insufficient spectral width of Yb 3+ -doped pure sesquioxide (e.g. Yb:Lu 2 O 3 : $13 nm, Yb:Sc 2 O 3 : $12 nm, Yb:Y 2 O 3 : $14 nm) 14 limits the development of ultrashort pulse generation.…”

“…[1][2][3][4] The investigation of crystal eld effects is demanded for Yb 3+ -based laser gain materials for a 1 mm emission, owing to the fact that energy level distributions are sensitive to crystal eld interactions. The weaker shielding effect of outer 5s 2 5p 6 for 4f 13 shell electrons in Yb 3+ ions enhances the effect of the crystal eld compared with other lanthanide ions. 5 A main feature of Yb 3+ -based lasers is their quasi-three-level operating scheme, in which the fundamental and terminal laser levels belong to the same groundstate manifold.…”

Optical rectification of ultrafast Yb lasers: pushing power and bandwidth of terahertz generation in GaP

“…To investigate the achievable power levels of our THz system, we utilized a power-scaled version of our TDL oscillator optimized for high-output power in the sub-100 fs regime as a compromise between achievable average power and shortest pulse duration. This laser configuration, described in detail in [16], delivers 95 fs transform-limited soliton pulses at 20 W average power and 48 MHz repetition rate, which corresponds to 3.9 MW peak power and 0.4 μJ pulse energy. The laser beam is focused into the generation crystal by a 200 mm focusing lens.…”

“…There has also been great progress recently in the development of ultrafast TDLs operating directly in the sub-100 fs regime [9][10][11][12][13][14]. The shortest pulse duration of ultrafast TDLs has been reduced to 30 fs [15], and power levels up to 20 W in 95b fs pulses and 155 W in 140 fs pulses have been achieved [16,17], making TDL oscillators very attractive sources to drive broadband high-power THz generation [18].…”