Project 1: Develop site-templated emitters in 2D materials and deterministically integrate them with frequency comb photonics

Two-dimensional (2D) semiconductors have emerged as a novel platform for quantum emitters in the visible to NIR wavelength range. Their 2D geometry is promising because it can enable high photon extraction efficiency and integration with photonic circuits fabricated in a range of materials. In addition, quantum emission from 2D materials can be localized by strain, as shown in Fig. A. The goals of this project are to: i) develop methods to grow site-templated quantum emitters in 2D materials at wafer scale via Molecular Beam Epitaxy (Chakraborty / Zide), ii) identify, through both first-principles theory (see Fig B) and experiment, the 2D material, doping, and strain conditions that provide the best quantum emitters (Janotti / Chakraborty), iii) develop Kerr micro-resonators that can implement spectral transduction of the photons emitted from the 2D material to a device-level standard wavelength (see Fig C) (Drake),  iv) use strain-driven localization to deterministically couple single quantum emitters in a 2D material to such a Kerr micro-resonator, and v) explore the properties of spin-based qubits hosted in these quantum emitters. We focus on 2D transition metal dichalcogenides (TMDCs) that have a valley degree of freedom that can be manipulated and accessed through circularly polarized excitonic optical transitions and efficiently tuned via electric, magnetic and strain fields.

(a) An exciton forms when a photon excites an electron from the valence band to the conduction band and (b) is bound by the Coulomb interaction. In TMDCs, excitons can be funneled to specific locations by strain (c), localized to defects (d), or both for deterministically-placed single photon emitters (e).

Fig A Caption: (a) An exciton forms when a photon excites an electron from the valence band to the conduction band and (b) is bound by the Coulomb interaction. In TMDCs, excitons can be funneled to specific locations by strain (c), localized to defects (d), or both for deterministically-placed single photon emitters (e).

Fig B Caption: Ball and stick model of a typical supercell that will be used to study defects in 2D materials: (a) perspective, and (b) top view. A point defect is illustrated in red.

Fig B Caption: Ball and stick model of a typical supercell that will be used to study defects in 2D materials: (a) perspective, and (b) top view. A point defect is illustrated in red.

Fig C Caption: Spectral conversion of single photons from 2D material. (a) Four-wave mixing to transduce photons from 2D quantum emitters to telecom photons. (b) Tuning the pump wavelength to match quantum emitter properties allows transduction to a single telecom wavelength. (c) Micrograph of SiN Kerr-microresonator with access and drop waveguides

Fig C Caption: Spectral conversion of single photons from 2D material. (a) Four-wave mixing to transduce photons from 2D quantum emitters to telecom photons. (b) Tuning the pump wavelength to match quantum emitter properties allows transduction to a single telecom wavelength. (c) Micrograph of SiN Kerr-microresonator with access and drop waveguides. [ Ref 1 ]