Electrical excitation of superradiant intersubband plasmons

Abstract

We present a detailed experimental analysis on mid-infrared superradiant emission from highly doped quantum wells. The emission originates from the radiative decay of intersubband plasmon excitations, which are electrically injected by directly contacting the two-dimensional electron gas. For the experiment, we processed an InGaAs/AlInAs quantum well into a three terminal field effect transistor with a leaky gate. Depending on the current pathway, we observe either a purely thermal excitation (source to drain injection) or a combination between thermal and resonant excitations (gate to source and drain injection). The scaling of the optical power with the density of electrons in the channel is in excellent agreement with the superradiant nature of the plasmon decay.