InAs-doped silica films for saturable absorber applications

InAs-doped thin silica films having saturable absorption properties were fabricated using rf sputtering. The films contain semiconductor nanoparticles preserving the zincblende crystal structure of bulk InAs. We have investigated the linear and nonlinear optical as well as structural properties of the films. Rapid thermal annealing in nitrogen was successfully used to tailor the optical absorption saturation dynamics. The films having saturable absorber properties were applied to Kerr lens mode locking initiation in a $Ti:Al2O3$ laser resulting in self-starting mode locking operation with pulses as short as 25 fs.