Non-equilibrium ultrashort pulse generation strategies in VECSELs

Vertical external cavity surface emitting lasers are ideal testbeds for studying nonlinear many-body systems driven far from equilibrium. The classical laser gain picture fails, however, when a high peak intensity optical pulse of duration shorter than the intrinsic carrier scattering time interacts with electrons in the conduction and holes in the valence band, and the non-equilibrium carrier distributions cannot recover during the presence of the exciting pulse. We present the optimization of ultrashort mode-locked pulses in a vertical external cavity surface emitting laser cavity with a saturable absorber mirror by modelling non-equilibrium quantum dynamics of the electron-hole excitations in the semiconductor quantum-well gain and absorber medium via the semiconductor Bloch equations and treating the field propagation at the level of Maxwell's wave equation. We introduce a systematic design that predicts the generation of stable mode-locked pulses of duration less than twenty femtoseconds. This factor of five improvement is of interest for mode-locking and ultrafast semiconductor dynamics applications. (C) 2017 Optical Society of AmericaAir Force Office of Scientific Research (AFOSR) [FA9550-14-1-0062]Open access journal.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu