Excitonic interactions with intense terahertz pulses in ZnSe/ZnMgSSe multiple quantum wells

Abstract

We studied the interaction of excitons with terahertz (THz) electric fields in ZnSe/ZnMgSSe multiple quantum wells with THz-pump and optical-probe spectroscopy. The incident THz pulse with a peak electric field of $\ensuremath{\sim}70\text{ }\text{kV}/\text{cm}$ induces strong spectral modulations in the heavy-hole and light-hole excitonic absorption resonances. The dependence of the excitonic absorption resonance energy on the THz field follows the Stark effect for smaller THz fields. For larger THz fields, the peak shift deviates from the Stark effect, which implies that the interaction enters the nonperturbative regime.