Chirped circular dielectric gratings for near-unity collection efficiency from quantum emitters in bulk diamond

Abstract

Efficient collection of fluorescence from nitrogen vacancy (NV) centers in diamond underlies the spin-dependent optical read-out that is necessary for quantum information processing and enhanced sensing applications. The optical collection efficiency from NVs within diamond substrates is limited primarily due to the high refractive index of diamond and the non-directional dipole emission. Here we introduce a light collection strategy based on chirped, circular dielectric gratings that can be fabricated on a bulk diamond substrate to modify an emitter's far-field radiation pattern. Using a genetic optimization algorithm, these grating designs achieve 98.9% collection efficiency for the NV zero-phonon emission line, collected from the back surface of the diamond with an objective of aperture 0.9. Across the broadband emission spectrum of the NV (600-800 nm), the chirped grating achieves 82.2% collection efficiency into a numerical aperture of 1.42, corresponding to an oil immersion objective again on the back side of the diamond. Our proposed bulk-dielectric grating structures are applicable to other optically active solid state quantum emitters in high index host materials.

A monolithic immersion metalens for imaging solid-state quantum emitters

“…Beyond lenses, the expanding body of research on metasurface design can be leveraged to explore phase profiles that shape emission from quantum emitter ensembles 34 , compensate for an emitter’s dipole orientation 35 , control coupling to orbital–angular–momentum modes 24, 36, 37 , and enable chiral quantum photonics 38 . An immersion metasurface can also be incorporated with nanophotonic structures for Purcell enhancement, for example to collimate the output of a chirped grating structure 39, 40 or parabolic mirror 41 through the backside of the diamond, or to extend the cavity length of a fiber-based resonator cavity 42 .…”

“…The electric-field intensity distribution in Fig. 3a was simulated in a similar manner by adding the intensity distributions resulting from two independent simulations of current sources with orientations corresponding to the two optical dipoles of the NV center 40 . This simulation was run using a 30.0 × 30.0 × 34.0 μm cell with PML boundaries.…”

Construction and operation of a tabletop system for nanoscale magnetometry with single nitrogen-vacancy centers in diamond

“…55,56 The dipole emission pattern of the NV center also contributes to the low collection efficiency. 57,58 Typically, less than 10% of the photons emitted from the NV center enters into the objective lens. Various approaches to enhancing the collection efficiency, such as the use of a solid immersion lens or a photonic waveguide, have been demonstrated.…”

Single-photon sources in diamond, silicon carbide and gallium nitride

“…b, The chirped diamond grating to enhance the emission of the grating, by fabricating this structure, the near-unity collection efficiency of the NV center has been achieved. C Simulation from the side, there is two interfaces, air to the grating and grating with the diamond [166].…”

“…In the rotating frame with the operator Another possible structure is the chirped diamond grating which is fabricated on the diamond membrane [166]. It is a designed photonic structure and the emitter is sitting in the center of the grating.…”