Purcell-Enhanced Single Photon Source Based on a Deterministically Placed WSe₂ Monolayer Quantum Dot in a Circular Bragg Grating Cavity

Abstract

We demonstrate a deterministic Purcell-enhanced single-photon source realized by integrating an atomically thin WSe2 layer with a circular Bragg grating cavity. The cavity significantly enhances the photoluminescence from the atomically thin layer, and supports single-photon generation with g (2) (0)<0.25. We observe a consistent increase of the spontaneous emission rate for WSe2 emitters located in the center of the Bragg grating cavity. These WSe2 emitters are self-aligned and deterministically coupled to such a broadband cavity, configuring a new generation of deterministic single-photon sources, characterized by their simple and low-cost production and intrinsic scalability.

Single‐Photon Emitters in Layered Van der Waals Materials

“…[130,138] Similarly, an Al 0.31 Ga 0.69 As circular Bragg grating bullseye cavity covered by a WSe 2 monolayer can significantly enhance the PL from a strain-defined SPE in the center of the structure (Figure 6c) with a Purcell factor of F P % 5. [139] Dielectric nanoantennas made from high-refractive-index materials can confine broadband optical modes with very small mode volumes with the advantage of low nonradiative losses [132] (Figure 6d). Covering the nanoantennas with WSe 2 leads to the activation of SPEs coupled to the optical mode, which is found to enhance the PL by a factor of 10 2 to 10 4 compared to strain activated SPEs by a low-refractive-index SiO 2 nanopillar.…”

“…Reproduced with permission. [ 139 ] Copyright 2021, American Chemical Society. d) Dielectric GaP nanoantennas covered with .…”

“…[ 130,138 ] Similarly, an circular Bragg grating bullseye cavity covered by a monolayer can significantly enhance the PL from a strain‐defined SPE in the center of the structure (Figure 6c) with a Purcell factor of . [ 139 ]…”

Atomically-thin Single-photon Sources for Quantum Communication

“…Semiconductor quantum dots [5,6] and color centers in diamond [7] are currently the main candidates among quantum emitters in the solid-state. However, monolayers of transition metal dichalcogenides (TMDCs) encounter increasing interest, due to the ease and flexibility in engineering their photonic properties and their straight-forward integration in photonic devices [8][9][10][11]. Single-photon emission from trapped excitons in atomically thin crystals was initially confirmed in monolayers of WSe 2 [12][13][14][15][16] and later complemented using WS 2 [17], MoS 2 [18,19] and MoTe 2 [20].…”

“…In addition, correlated pair emission from the biexciton-exciton radiative cascade was experimentally shown in WSe 2 [21], outlining the possibility to generate entangled-photon pairs. From a technological viewpoint, TMDC-based quantum light sources feature interesting advantages over other solid-state implementations: a relatively simple and low-cost fabrication, the tailoring of the excitonic properties via multi-stacking of monolayers [22], giant susceptibility to external strain [23], and a deterministic control on the spatial position of the quantum emitters [24,25], even in optical cavi-ties [10]. In addition, TMDC-based single-photon sources cover all three telecom windows centered around 850 nm, 1300 nm, and 1550 nm [20], including wavelengths compatible with atomic transitions used for quantum memories [26].…”