The reduced temporal parameters of passivated semiconductor saturable absorber mirror

It is shown that plasma-enhanced chemical-vapor deposition Of SiO2 antireflective layer can result in significant reduction of the recovery time of semiconductor saturable absorber mirror (SESAM). The results were compared to the SESAM structure capped by SiNX layer and native oxide. The recovery time of the SESAM devices was characterized by pump-probe measurements. We have obtained recovery times of 25 ps, 11 ps and 2.6 ps for native oxide, SiNX and SiO2 layers, respectively. These results can be explained by differences in the density of surface states which exist after passivation processes. Using SESAM with an SiO2 antireflective cap layer, we have demonstrated a mode-locked diode-pumped Yb:KY(WO4)(2) laser generating near band-width limited pulses. We have used the passivation process to reduce the pulse duration. (C) 2009 Elsevier B.V. All rights reserved.