43 fs pulse generation from a SESAM mode-locked Tm,Ho:CALYGLO laser

By employing a novel, to the best of our knowledge, "mixed" Tm,Ho:CaYGdLuAlO₄ crystal, which exhibits a broad emission spectrum due to the inhomogeneous line broadening with structural and compositional disorder, sub-50 fs pulses have been demonstrated at 2 μm. Further enhancing the self-phase modulation (SPM) effect, pulse as short as 43 fs can be achieved at 2080 nm (σ-polarizations), with a spectral bandwidth of 114 nm, which shows the potential of Tm,Ho co-doped "mixed" aluminate crystals for generating few-optical-cycle pulses in the 2-μm spectral range.