Sub-6-fs pulses from a SESAM-assisted Kerr-lens modelocked Ti:sapphire laser: at the frontiers of ultrashort pulse generation

Abstract.Well-characterized pulses in the two-optical-cycle regime are demonstrated using a Kerr-lens modelocked (KLM) Ti:sapphire laser and phase-sensitive diagnostics. The oscillator employs double-chirped mirrors (DCMs) for dispersion compensation, spectral shaping via wavelength-dependent output coupling, and a semiconductor saturable absorber mirror (SESAM) for reliable operation at up to 300 mW output power and with a repetition rate of ∼90 MHz.In the discussion of the experimental results we emphasize how spectral shaping can be used most efficiently in the generation of the shortest possible pulse supported by the Ti:sapphire gain bandwidth.