Strong coupling of ionising transitions

TL;DR

This paper demonstrates that ionising electronic transitions can be strongly coupled to photonic resonances, creating new bound states that enable tuning of optical and electronic properties in semiconductor structures.

Contribution

It introduces a theoretical framework showing strong coupling of ionising transitions with photonic resonances, leading to novel bound states and tunable properties.

Findings

Strong coupling causes narrow resonances below ionisation threshold.

Creation of a bound state due to collective electron-photon interaction.

Potential for tuning optical and electronic properties in semiconductor devices.

Abstract

We demonstrate that a ionising transition can be strongly coupled to a photonic resonance. The strong coupling manifests itself with the appearance of a narrow optically active resonance below the ionisation threshold. Such a resonance is due to electrons transitioning into a novel bound state created by the collective coupling of the electron gas with the vacuum field of the photonic resonator. Applying our theory to the case of bound-to-continuum transitions in microcavity-embedded doped quantum wells, we show how those strong-coupling features can be exploited as a novel knob to tune both optical and electronic properties of semiconductor heterostructures.