# Phonon mediated conversion of exciton-polaritons Rabi oscillation into THz radiation

## TL;DR

This paper demonstrates that in Cadmium Telluride microcavities, Rabi oscillations can be converted into THz radiation through phonon-mediated processes, leveraging a resonance condition that enhances nonlinearity without changing cavity design.

## Contribution

It reveals a novel phonon-mediated mechanism enabling THz emission from exciton-polariton Rabi oscillations in CdTe microcavities, independent of cavity modifications.

## Key findings

- Resonance between Rabi splitting and phonon-polariton states enhances THz emission.
- Giant increase in second-order nonlinearity observed.
- THz radiation generated without altering microcavity design.

## Abstract

Semiconductor microcavities in the strong-coupling regime exhibit an energy scale in the THz frequency range, which is fixed by the Rabi splitting between the upper and lower exciton-polariton states. While this range can be tuned by several orders of magnitude using different excitonic medium, the transition between both polaritonic states is dipole forbidden. In this work we show that in Cadmium Telluride microcavities, the Rabi-oscillation driven THz radiation is actually active without the need for any change in the microcavity design. This feature results from the unique resonance condition which is achieved between the Rabi splitting and the phonon-polariton states, and leads to a giant enhancement of the second order nonlinearity.