Full optical SESAM characterization methods in the 1.9 to 3-µm wavelength regime.

Semiconductor saturable absorber mirrors (SESAMs) are widely used for modelocking of various ultrafast lasers. The growing interest for SESAM-modelocked lasers in the short-wave infrared and mid-infrared regime requires precise characterization of SESAM parameters. Here, we present two SESAM characterization setups for a wavelength range of 1.9 to 3 µm to precisely measure both nonlinear reflectivity and time-resolved recovery dynamics. For the nonlinear reflectivity measurement, a high accuracy (<0.04%) over a wide fluence range (0.1-1500 µJ/cm