Tailoring the Emission Wavelength of Color Centers in Hexagonal Boron Nitride for Quantum Applications

Abstract

Optical quantum technologies promise to revolutionize today’s information processing and sensors. Crucial to many quantum applications are efficient sources of pure single photons. For a quantum emitter to be used in such application, or for different quantum systems to be coupled to each other, the optical emission wavelength of the quantum emitter needs to be tailored. Here, we use density functional theory to calculate and manipulate the transition energy of fluorescent defects in the two-dimensional material hexagonal boron nitride. Our calculations feature the HSE06 functional which allows us to accurately predict the electronic band structures of 267 different defects. Moreover, using strain-tuning we can tailor the optical transition energy of suitable quantum emitters to match precisely that of quantum technology applications. We therefore not only provide a guide to make emitters for a specific application, but also have a promising pathway of tailoring quantum emitters that can couple to other solid-state qubit systems such as color centers in diamond.

Polarization dynamics of solid-state quantum emitters

“…We have studied the most likely candidates, e.g., intrinsic defects and complexes involving oxygen and carbon impurities with neutral or ±1 charge states. Carbon complexes could form during the SEM irradiation process, consistent with previous DFT calculations yielding 2 eV quantum emitters in hBN [23,31,32].…”

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“…The 698 nm pump laser system to excite the single photon source is adapted from a commercially available ECDL. This wavelength is compatible with hBN emitters having an optical transition above 700 nm [32,33], and it also matches the clock transition of neutral strontium atoms [34] (therefore it may also prove useful for future space missions with cold atom experiments). A ridge waveguide laser diode is integrated into a butterfly housing with an anti-reflective coated window, together with a thermoelectric cooler (TEC), a thermistor, an external volume Bragg grating at the front facet for controlled optical feedback, and two cylindrical lenses to collimate the output beam.…”

“…For the coupling of single photons to quantum memories, hBN emitters are a promising quantum light source. We have predicted a rich variety of fluorescent defects in hBN with transition energies compatible with many quantum memory platforms using density functional theory (DFT) [33]. We decided to work with alkali vaporbased QMs since devices with sufficiently small footprints have recently been developed for space applications [67].…”

“…Moreover, the tunability of such microcavities allows us to adapt the resonance wavelength to match exactly the atomic transition. By investigating 267 different emitters using DFT, we have identified the following defects emitting at relevant transitions in alkali vapors [33]: Here the defects are denoted in Kröger-Vink notation where e.g. the last listed defect complex consists of an erbium impurity replacing a boron atom next to a boron vacancy with a positive charge state.…”

Exploring the phonon-assisted excitation mechanism of luminescent centres in hexagonal boron nitride by photoluminescence excitation spectroscopy

“…During the final stage of the preparation of this manuscript we became aware about a thorough study of defects in hBN, focusing on tailoring the ZPL energy [46].…”