Simultaneously enhancing brightness and purity of WSe$_2$ single photon emitter using high-aspect-ratio nanopillar array on metal

TL;DR

This paper demonstrates a novel design using high-aspect-ratio nanopillar arrays on metal to significantly enhance brightness and purity of WSe$_2$ single photon emitters, achieving high emission rates suitable for quantum communication.

Contribution

The study introduces a high-aspect-ratio nanopillar array design that boosts emission rate and maintains high photon purity in WSe$_2$ emitters, surpassing previous limitations.

Findings

Achieved >10 MHz single photon emission rate in the 770-800 nm range.

Maintained high single photon purity even at increased emission rates.

Enhanced out-coupling efficiency with gold back reflector.

Abstract

Monolayer semiconductor transferred on nanopillar arrays provides site-controlled, on-chip single photon emission, which is a scalable light source platform for quantum technologies. However, the brightness of these emitters reported to date often falls short of the perceived requirement for such applications. Also, the single photon purity usually degrades as the brightness increases. Hence, there is a need for a design methodology to achieve enhanced emission rate while maintaining high single photon purity. Using WSe$_2$ on high-aspect-ratio ($\sim 3$ - at least two-fold higher than previous reports) nanopillar arrays, here we demonstrate $>10$ MHz single photon emission rate in the 770-800 nm band that is compatible with quantum memory and repeater networks (Rb-87-D1/D2 lines), and satellite quantum communication. The emitters exhibit excellent purity (even at high emission rates) and improved out-coupling due to the use of a gold back reflector that quenches the emission away from the nanopillar.