Recent advances of InGaSb SESAMs in the 2 to 2.4-µm wavelength regime

Abstract

We present the characterization under intracavity conditions of semiconductor saturable absorber mirrors (SESAMs) operating from 2 – 2.4 µm. The precise nonlinear reflectivity and recovery time measurement setups reveal excellent parameters of our in-house grown 2.05 and 2.4 µm SESAMs. Low saturation fluences around 4 µJ/cm2, percent range modulation depth, extremely low non-saturable losses and fast recovery within a few tens of picoseconds have been measured for all SESAMs. Using these SESAMs output power records in modelocking of vertical external-cavity surface-emitting lasers (VECSELs), thin-disk Ho:YAG lasers at 2 µm wavelength and Cr:ZnS lasers at 2.4 µm are achieved.