Directly diode-pumped, Kerr-lens mode-locked, few-cycle Cr:ZnSe oscillator

Lasers based on Cr2+-doped II-VI material, often known as the Ti:Sapphire of the mid-infrared, can directly provide few-cycle pulses with octave-spanning spectra, and serve as efficient drivers for generating broadband mid-infrared radiation. It is expected that the wider adoption of this technology benefits from more compact and cost-effective embodiments. Here, we report the first directly diode-pumped, Kerr-lens mode-locked Cr2+-doped II-VI oscillator pumped by a single InP diode, providing average powers over 500 mW and pulse durations of 45 fs - shorter than six optical cycles at 2.4 mu m. These correspond to a sixty-fold increase in peak power compared to the previous diode-pumped record, and are at similar levels with respect to more mature fiber-pumped oscillators. The diode-pumped femtosecond oscillator presented here constitutes a key step toward a more accessible alternative to synchrotron-like infrared radiation and is expected to accelerate research in laser spectroscopy and ultrafast infrared optics. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement