An ion-implanted anti-resonant Fabry Perot saturable absorber for passive mode-locking of solid state lasers

We have fabricated GaAs based anti-resonant Fabry-Perot saturable absorbers (A-FPSAs) for passively mode-locking near infrared solid state lasers, using Metal Organic Vapour Phase Epitaxy (MOVPE) growth followed by ion-implantation and optional thermal annealing. We present differential reflectivity measurements showing the effect of ion implantation and annealing. The devices were characterised for their large signal response including saturation fluence, modulation depth and non-bleachable losses-important parameters for passive mode-locking. Finally we demonstrate mode-locking using our samples within a Ti:sapphire laser observing stable and reliable self-starting, pulses in the 100 fs range, and 50 nm tunability. Results of computer simulations are in good agreement with the experiments.