Semiconductor quantum well irradiated by a two-mode electromagnetic field as a terahertz emitter

TL;DR

This paper theoretically investigates how a semiconductor quantum well, driven by a two-mode electromagnetic field, can generate terahertz radiation through nonlinear optical effects involving dynamic Stark gaps and electron oscillations.

Contribution

It introduces a model showing how a two-mode electromagnetic field induces terahertz emission in a quantum well via dynamic Stark gaps and electron oscillations.

Findings

Dynamic Stark gaps restrict electron oscillation amplitudes.

Frequency comb emission is generated from the quantum well.

The system can be used for optically controlled terahertz generation.

Abstract

We study theoretically the nonlinear optical properties of a semiconductor quantum well (QW) irradiated by a two-mode electromagnetic wave consisting of a strong resonant dressing field and a weak off-resonant driving field. In the considered strongly coupled electron-field system, the dressing field opens dynamic Stark gaps in the electron energy spectrum of the QW, whereas the driving field induces electron oscillations in the QW plane. Since the gapped electron spectrum restricts the amplitude of the oscillations, the emission of a frequency comb from the QW appears. Therefore, the doubly-driven QW operates as a nonlinear optical element which can be used, particularly, for optically controlled generation of terahertz radiation.