Photonic devices fabricated from (111)‐oriented single crystal diamond

Abstract

Diamond is a material of choice in the pursuit of integrated quantum photonic technologies. So far, the majority of photonic devices fabricated from diamond, are made from (100)-oriented crystals. In this work, we demonstrate a methodology for the fabrication of optically-active membranes from (111)-oriented diamond. We use a liftoff technique to generate membranes, followed by chemical vapour deposition of diamond in the presence of silicon to generate homogenous silicon vacancy colour centers with emission properties that are superior to those in (100)-oriented diamond. We further use the diamond membranes to fabricate high quality microring resonators with quality factors exceeding ~ 3000. Supported by finite difference time domain calculations, we discuss the advantages of (111) oriented structures as building blocks for quantum nanophotonic devices.Diamond is an attractive platform for studies of light-matter interaction at the nanoscale[1-7]. In the past decade, defects in diamond, also known as color centers, have emerged as attractive candidates for scalable solid state quantum photonic architectures [1,6]. While earlier works were focused predominantly on nitrogen vacancy (NV) centres [8,9], recent effort is devoted to group IV defects [10][11][12][13][14][15], (e.g. the silicon vacancy (SiV)) due to their narrowband emission and a better resilience to electromagnetic fluctuations.Integration of these color centres with photonic resonators is an important challenge for several reasons. First, it enables enhancement of the photon emission flux from the single color centres (for instance by using diamond pillars [16]). Second, it provides the means to interconnect potential quantum nodes in a large network, where the emitters are coupled to individual cavities and interconnected with a waveguide [17,18]. Last, if the photonic resonator is carefully designed with coupled directional emission, one can achieve high cavity cooperativity and realise advanced quantum phenomena such as single photon switch with a solid state system [19]. However, despite the remarkable progress in nanofabrication of diamond cavities [8,20], all photonic resonators to date were fabricated from (100)-oriented diamond, primarily because this is the most common orientation provided by commercial suppliers and the difficulty in engineering and polishing (111) oriented crystals [21]. This, however, limits the potential coupling strength of many color centers to cavities since most centers studied to date have dipoles oriented along the <111> direction, and the dipole overlap with the cavity field is therefore not optimal in cavities fabricated from (100)-oriented diamond. Conversely, in (111)-oriented diamond, the overlap is optimal, and superior Purcell enhancement is expected.In the current work, we fabricated large area (111) diamond membranes that exhibit bright SiV luminescence. Consequently, these membranes were utilized to engineer high quality diamond microring resonators with quality factors of ~ 3000. Our work launches a new ...

Novel color center platforms enabling fundamental scientific discovery

“…The SEM images of (clockwise from top left)—Passive devices in diamond : Free standing diamond tapered waveguides for efficient coupling 152 (Reprinted with permission from Burek et al 152 ), inverse designed vertical coupler in diamond 151 (reprinted with permission from Dory et al 151 ), array of diamond nanowires 148 (reprinted with permission from Hausmann et al 148 ); active devices in diamond: 2D crystal cavities with defects (L3 cavity) 154 (reprinted with permission from Wan et al 154 ), 1D nanobeam photonic cavities fabricated using angled‐etching 155 (reprinted with permission from Sun et al 155 ), Microring resonator in (111) diamond membrane on top of SiO 2 substrate, containing SiV 156 (reprinted with permission from Regan et al 156 ); Passive devices in SiC: Nanopillars in 4H‐SiC 146 (reprinted with permission from Radulaski et al 146 ), solid immersion lens fabricated on the surface of 4H‐SiC 27 (reprinted with permission from Widmann et al 27 ); active devices in SiC: 1D nanobeam photonic crystal cavity in 4H‐SiC 157 (reprinted with permission from Bracher et al 157 ), 1D nanobeam with triangular cross‐section fabricated using oblique plasma etching in 4H‐SiC 158 (reprinted with permission from Song et al 158 ); hybrid passive devices: pillars on the surface of single crystal diamond to create an immersion metalens 150 (reprinted with permission from Huang et al 150 ); hybrid active devices: Si ring resonator on 4H‐SiC 159 (reprinted with permission from Wang et al 159 ), hybrid SiC‐nanodiamond microdisk array 6 (reprinted with permission from Radulaski et al 6 ), hybrid GaP‐diamond whispering gallery mode nanocavity 160 (reprinted with permission from Barclay et al 160 )…”

Hierarchical Micro/Nanostructured Diamond Gradient Surface for Controlled Water Transport and Fog Collection

“…Inorganic nanoparticles, [ 22,23 ] graphene, [ 24 ] carbon nanotube, [ 25,26 ] and diamond coatings [ 27 ] were introduced into this research field to address these issues. Diamond is a promising candidate as it offers plenty of outstanding properties, such as high thermal conductivity, [ 28–31 ] excellent wear resistance, [ 8,32 ] chemical inertness, [ 33,34 ] corrosion resistance, [ 35 ] quantum photonic, [ 36 ] and good biocompatibility. [ 8,37–40 ] It is possible to tailor the microstructure of the diamond coatings.…”

Fabrication of High‐Quality Thin Single‐Crystal Diamond Membranes with Low Surface Roughness

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Single-crystal diamond (SCD) in particular in form of thin membranes [1][2][3] has gained an ever-increasing scientific interest over the years based on diamond's exceptional optical [4,5] and electrical [6,7] properties. Therefore, it has emerged as a highly promising platform e.g., in the field of nanophotonics for photonic integrated devices [8][9][10] and envisioned applications in quantum information technologies (QITs), such as quantum memories [11,12] and quantum communication. [13,14] Different kinds of optically active point defects in the SCD lattice, the so-called color centers like the nitrogen-vacancy (NV) center [15,16] or the silicon-vacancy (SiV) center, [17,18] show favorable characteristics, e.g., high photostability at room temperature and practicable control of coherent single spins, to serve as single-photon emitters in QITs.However, due to the high refractive index of diamond (n d % 2.41) [19] inducing total internal reflection at the diamond-air interface, light-confining architectures like nanopillars, [20,21] solid immersion lenses, [22,23] photonic crystal cavities [24,25] or Fabry-Pérot microcavities [26] are necessary to yield an efficient outcoupling from the zero-phonon line (ZPL) of the color centers and to improve the photon collection efficiency.

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“…Single-crystal diamond (SCD) in particular in form of thin membranes [1][2][3] has gained an ever-increasing scientific interest over the years based on diamond's exceptional optical [4,5] and electrical [6,7] properties. Therefore, it has emerged as a highly promising platform e.g., in the field of nanophotonics for photonic integrated devices [8][9][10] and envisioned applications in quantum information technologies (QITs), such as quantum memories [11,12] and quantum communication. [13,14] Different kinds of optically active point defects in the SCD lattice, the so-called color centers like the nitrogen-vacancy (NV) center [15,16] or the silicon-vacancy (SiV) center, [17,18] show favorable characteristics, e.g., high photostability at room temperature and practicable control of coherent single spins, to serve as single-photon emitters in QITs.…”