A monolithic immersion metalens for imaging solid-state quantum emitters

Abstract

Quantum emitters such as the diamond nitrogen-vacancy (NV) center are the basis for a wide range of quantum technologies. However, refraction and reflections at material interfaces impede photon collection, and the emitters’ atomic scale necessitates the use of free space optical measurement setups that prevent packaging of quantum devices. To overcome these limitations, we design and fabricate a metasurface composed of nanoscale diamond pillars that acts as an immersion lens to collect and collimate the emission of an individual NV center. The metalens exhibits a numerical aperture greater than 1.0, enabling efficient fiber-coupling of quantum emitters. This flexible design will lead to the miniaturization of quantum devices in a wide range of host materials and the development of metasurfaces that shape single-photon emission for coupling to optical cavities or route photons based on their quantum state.

Optimization of a Diamond Nitrogen Vacancy Centre Magnetometer for Sensing of Biological Signals

“…In particular, improvements in CVD growth, nitrogen levels and conversion to NV − centers, optimization of irradiation and dealing with material strain. Patterning of the diamond may allow a greater fraction of the fluorescence to escape, boosting efficiency [49].…”

Adjoint-optimized nanoscale light extractor for nitrogen-vacancy centers in diamond

“…It is instructive to compare the FoM of our NLE (∼35 for NVs at a depth of 10 nm) with some existing structures in the literature designed for broadband vertical outcoupling of light from a diamond slab, with the understanding that the FoM combines the distinct collection-enhancement and Purcell mechanisms. Dielectric structures comprising etched diamond typically do not provide much Purcell enhancement and include bullseye gratings [21], vertical nanowires [49], solid-immersion metalenses [19], and parabolic reflectors [13]; we estimate that these structures have calculated FoMs of approximately 10-20 due entirely to collection enhancement. Resonant geometries proposed thus far have primarily relied on plasmonic enhancement in structures such as metallic cavities [14,50] and gratings [51], with FoMs of up to ∼35.…”

“…However, efficiently extracting NV fluorescence is often challenging due to the high index of refraction in diamond (∼2.4), which results in high reflectance at the diamond-air interfaces and total internal reflection for emission angles larger than the critical angle. Previous attempts to extract more light from bulk diamond primarily involved the etching of the diamond itself (a complicated fabrication process that can adversely affect NV properties such as spin coherence) [13][14][15][16][17][18][19] or fabricating structures that still required a high-numerical-aperture oil-immersion objective to efficiently collect the emission (which adds system complexity and is detrimental to sensing applications) [20][21][22][23]. Furthermore, precision etching of diamond around NV centers can be a substantial challenge and can damage the surface of diamond, resulting in roughness and modification of the chemical termination [24], which can degrade the quantum properties of NV centers [25,26].…”

A simple transfer-matrix model for metasurface multilayer systems

“…This notion revitalized a venerable history in grating science, particularly the notion of echelette gratings to shape diffraction [4]. Recent demonstrations of metasurfaces include a large variety of flat optics components, such as lenses [5][6][7][8], waveplates and polarization optics [9][10][11], as well as holograms [9][10][11], diffusers [12], and even computational metasurfaces that are designed to perform simple linear mathematical operations on incident wavefronts [13][14][15]. In this work we focus on 2D arrays where the constituents are strong, resonant scatterers with a dipolar plasmonic resonance, as opposed to dielectric metasurfaces [3,16].…”