Site-Controlled Purcell-Induced Bright Single Photon Emitters in Hexagonal Boron Nitride

TL;DR

This paper demonstrates large-area arrays of site-controlled single photon emitters in hexagonal boron nitride using plasmonic nanoresonators, significantly enhancing emission rates and paving the way for scalable quantum photonic devices.

Contribution

The work introduces a novel plasmonic nanoresonator architecture for deterministic placement and enhancement of SPEs in hBN at room temperature.

Findings

Achieved a Purcell factor of 4.9 and a saturated emission rate over 3.8 million counts/sec.

Demonstrated a five-fold reduction in SPE lifetime to 480 ps.

Realized a 21% yield of bright, site-controlled SPEs in large-area arrays.

Abstract

Single photon emitters (SPEs) hosted in hexagonal boron nitride (hBN) are essential elementary building blocks for enabling future on-chip quantum photonic technologies that operate at room temperature. However, fundamental challenges, such as managing non-radiative decay, competing incoherent processes, as well as engineering difficulties in achieving deterministic placement and scaling of the emitters, limit their full potential. In this work, we experimentally demonstrate large-area arrays of plasmonic nanoresonators for Purcell-induced site-controlled SPEs by engineering emitter-cavity coupling and enhancing radiative emission at room temperature. The plasmonic nanoresonator architecture consists of gold-coated silicon pillars capped with an alumina spacer layer, enabling a 10-fold local field enhancement in the emission band of native hBN defects. Confocal photoluminescence and second-order autocorrelation measurements show bright SPEs with sub-30 meV bandwidth and a saturated emission rate of more than 3.8 million counts per second. We measure a Purcell factor of 4.9, enabling average SPE lifetimes of 480 ps, a five-fold reduction as compared to emission from gold-free devices, along with an overall SPE yield of 21%. Density functional theory calculations further reveal the beneficial role of an alumina spacer between defected hBN and gold, as an insulating layer can mitigate the electronic broadening of emission from defects proximal to gold. Our results offer arrays of bright, heterogeneously integrated quantum light sources, paving the way for robust and scalable quantum information systems.