PICOSECOND SATURABLE ABSORPTION-MEASUREMENTS ON THIN-FILM SINGLE-CRYSTAL INAS LAYERS GROWN BY MBE

The linear and non-linear optical properties of high-quality single-crystal thin (3.3-mu-m) MBE films of InAs on GaAs substrates are studied using the lambda = 2.94-mu-m output of a mode-locked Er3+ laser. The onset of absorption saturation occurs at pulse energy densities of almost-equal-to 100-mu-J cm-2, and a dynamic Moss-Burstein effect model gives a good quantitative explanation of the experimental data. Very rapid absorption recovery times (almost-equal-to 150 ps) suggest that interfacial recombination is the dominant relaxation mechanism, and indicate the potential for the use of these novel semiconductor heterostructures as fast passive optical shutters for mode-locking and Q-switching applications in the mid-infrared.