Temperature Dependence of Highly Excited Exciton Polaritons in Semiconductor Microcavities

TL;DR

This paper investigates how temperature affects the photoluminescence and lasing mechanisms of highly excited exciton polaritons in semiconductor microcavities, revealing potential alternative photon lasing mechanisms at high excitation and low temperature.

Contribution

It provides experimental insights into the temperature dependence of photon lasing mechanisms in highly excited polariton systems, highlighting the persistence of electron-hole pairs at high excitation.

Findings

Second threshold for standard photon lasing not observed at low temperatures

Electron-hole pairs may still exist at high excitation regimes

Different photon lasing mechanisms are suggested at low temperatures

Abstract

Observations of polariton condensation in semiconductor microcavities suggest that polaritons can be exploited as a novel type of laser with low input-power requirements. The low-excitation regime is approximately equivalent to thermal equilibrium, and a higher excitation results in more dominant nonequilibrium features. Although standard photon lasing has been experimentally observed in the high excitation regime, e-h pair binding can still remain even in the high-excitation regime theoretically. Therefore, the photoluminescence with a different photon lasing mechanism is predicted to be different from that with a standard photon lasing. In this paper, we report the temperature dependence of the change in photoluminescence with the excitation density. The second threshold behavior transited to the standard photon lasing is not measured at a low-temperature, high-excitation power regime. Our results suggest that there may still be an electron--hole pair at this regime to give a different photon lasing mechanism.