Multimode Nanobeam Photonic Crystal Cavities for Purcell Enhanced Quantum Dot Emission

TL;DR

This paper designs GaAs photonic crystal nanobeam cavities that optimize quantum dot placement to reduce linewidth broadening while maintaining high quality factors, enabling enhanced single-photon emission for quantum photonics.

Contribution

It introduces a novel nanobeam cavity design that balances quantum dot positioning with multimode propagation to achieve high Q factors and Purcell enhancements.

Findings

Achieved resonances with quality factors around 10^3.

Maximized quantum dot distance from sidewalls to reduce spectral broadening.

Potential for Purcell radiative rate enhancements of approximately 100.

Abstract

Epitaxial III-V semiconductor quantum dots in nanopthonic structures are promising candidates for implementing on-demand indistinguishable single-photon emission in integrated quantum photonic circuits. Quantum dot proximity to the etched sidewalls of hosting nanophotonic structures, however, has been shown to induce linewidth broadening of excitonic transitions, which limits emitted single-photon indistinguishability. Here, we design and demonstrate GaAs photonic crystal nanobeam cavities that maximize quantum dot distances to etched sidewalls beyond an empirically determined minimum that curtails spectral broadening. Although such geometric constraint necessarily leads to multimode propagation in nanobeams, which significantly complicates high quality factor cavity design, we achieve resonances with quality factors $Q\approx10^3$, which offer the potential for achieving Purcell radiative rate enhancements $F_p\approx100$.