Circularly polarized cavity-mode emission from quantum dots in a semiconductor three-dimensional chiral photonic crystal

TL;DR

This paper demonstrates a chiral photonic crystal that produces circularly polarized cavity-mode emission from quantum dots, potentially enabling advanced photonic and quantum devices with tailored polarization properties.

Contribution

The study experimentally shows circularly polarized cavity modes in a GaAs-based chiral photonic crystal with embedded quantum dots, revealing polarization-dependent modifications of the optical density of states.

Findings

Observation of a polarization bandgap for left-handed circular light

Detection of a cavity-mode peak with opposite circular polarization

Enhanced control of circular polarization in quantum dot emission

Abstract

We experimentally demonstrated a circularly polarized cavity mode in a GaAs-based chiral photonic crystal (PhC) containing a planar defect. Low-temperature photoluminescence measurements of InAs quantum dots (QDs) embedded in the planar defect revealed a polarization bandgap for left-handed circularly polarized light in the near-infrared spectrum. Within this bandgap, where the QDs preferably emitted right-handed circularly polarized light, we observed a distinct cavity-mode peak characterized by left-handed circular polarization. This observation indicates that the chiral PhC modifies the optical density of states for left-handed circular polarization to be suppressed in the polarization bandgap and be largely enhanced at the cavity mode. The results obtained may not only provide photonic devices such as compact circularly polarized light sources but also promote strong coupling between circularly polarized photons and excitons in solid states or molecules, paving the way for advancements in polaritonics, spintronics, and quantum information technology.