Integration of hBN Quantum Emitters in Monolithically Fabricated Waveguides

Abstract

Hexagonal boron nitride (hBN) is gaining interest for potential applications in integrated quantum nanophotonics. Yet, to establish hBN as an integrated photonic platform several cornerstones must be established, including the integration and coupling of quantum emitters to photonic waveguides. Supported by simulations, we study the approach of monolithic integration, which is expected to have coupling efficiencies that are ~ 4 times higher than those of a conventional hybrid stacking strategy. We then demonstrate the fabrication of such devices from hBN and showcase the successful integration of hBN single photon emitters with a monolithic waveguide. We demonstrate coupling of single photons from the quantum emitters to the waveguide modes and on-chip detection. Our results build a general framework for monolithically integrated hBN single photon emitter and will facilitate future works towards on-chip integrated quantum photonics with hBN.

Excited-state spin-resonance spectroscopy of V$_\text{B}^-$ defect centers in hexagonal boron nitride

“…Additionally, a study of the hyperfine splitting near the ELAC could shed light on the coupling to nuclear spins [30], which could have applications in long-lived spin-based memories [42] or quantum simulation [43]. Rapid progress is being made in integrating hBN defects into nano-photonic devices with waveguides [13] and optical cavities [14,44] to achieve high signal-to-noise ratios for sensing applications. We also envision using V − B defects as quantum sensors [16] for magnetization of layered out-of-plane magnets like CrI 3 and CrBr 3 .…”

“…Optically addressable, spin-active defects and quantum dots in the solid-state have emerged as promising qubits and quantum sensors [1,2,3] because robust control techniques enable facile quantum gates and sensing protocols [4]. The recent advent of two-dimensional (2D) materials has stimulated the search for spin-active defects that can be integrated into van der Waals heterostructures, enabling a wide array of optoelectronic and nanophotonic devices that take advantage of its optical and spin properties [5,6,7,8,9,10,11,12,13,14]. A spin-active defect in a 2D material is especially promising for nanoscale sensing of interfacial phenomena with high sensitivity due to narrow spin transition linewidths and the ability to position these atomic-scale systems at sub-nanometer distances from the surface of a sample [15,16].…”

Single‐Photon Emitters in Layered Van der Waals Materials

“…Since hBN is a wide bandgap material with a high refractive index, the material is well suited for fabricating nanophotonic structures. [ 154 ] Recently, the monolithic integration of an hBN SPE in an hBN waveguide was demonstrated and a maximum coupling efficiency for this structure of the SPE emission into the waveguide was calculated to be 37% [ 155 ] (Figure 7e).…”

“…e) Monolithical integration of SPEs in hBN by fabrication of an hBN waveguide. Reproduced with permission [155]. Copyright 2021, American Chemical Society.…”

Scalable integration of quantum emitters into photonic integrated circuits

“…Randomly placed emitters in the QDs [72] High Yes Yes wave guides introduce high photon losses. SiC-color centers [114] H i g h Y e s Y e s hBN [115] H i g h Y e s Y e s G-centers in silicon [34][35][36] H i g h Y e s Y e s Monolithic (deterministic) SiV centers in SiC [69,70] Low Yes No SiC: yield of emitter creation via ion implantation has to be improved. QDs [76] High No No QDs: well-performing site-controlled QDs have to be produced.…”