Optically Pumped GaSb-Based Thin-Disk Laser Design Considerations for CW and Dual-Comb Operation at a Center Wavelength Around 2 μm

This paper reviews the key achievements leading to the first demonstration of a passively modelocked optically pumped thin-disk semiconductor laser, where both the saturable absorber and the gain quantum wells are integrated into a single semicon- ductor chip, known as the Modelocked Integrated eXternal-cavity Surface Emitting Laser (MIXSEL).

This GaSb-based MIXSEL operates at a center wavelength of 2 µm, supporting both single and dual-comb operations, with an average output power of 30 to 50 mW, pulse repetition rates of approximately 4 GHz, and picosecond pulse durations. It enables initial proof-of-principle dual-comb spectroscopy measurements. For this, we optimized continuous wave (cw) Vertical External Cavity Surface Emitting Laser (VECSEL) operation at 2 µm without an intracavity heat- spreader, enhanced group delay dispersion (GDD) compensation, and introduced an additional pump mirror integration.