Nonlinear ultrafast optical absorption and pump-probe spectroscopy in biased semiconductor superlattices

Abstract

We present theoretical simulations of two important nonlinear optical phenomena in biased semiconductor superlattices: nonlinear ultrafast absorption and pump-probe spectroscopy. We find that for both these techniques, the excitonic Wannier-Stark ladder absorption peaks shift as the optical intensity is increased. We show that both of these measurements can be used to probe the ultrafast internal intraband electric field within the superlattice. We employ a nonperturbative formalism in an excitonic basis to model the dynamic response. This allows us to self-consistently include the self-generated internal intraband field that generates the spectral peak shifts.