Quantum Photonic Interface for Tin-Vacancy Centers in Diamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-07-26 |
| Journal | Physical Review X |
| Authors | Alison E. Rugar, Shahriar Aghaeimeibodi, Daniel Riedel, Constantin Dory, Haiyu Lu |
| Institutions | Stanford University, SLAC National Accelerator Laboratory |
| Citations | 95 |
| Analysis | Full AI Review Included |
A Quantum Photonic Interface for Tin-Vacancy Centers in Diamond
Section titled âA Quantum Photonic Interface for Tin-Vacancy Centers in DiamondâAnalysis of arXiv:2102.11852v1 by Rugar et al. (Stanford University)
This document analyzes the technical requirements and achievements of the research paper concerning the integration of Tin-Vacancy (SnV-) centers in diamond with photonic crystal cavities, and maps these requirements directly to the advanced MPCVD diamond solutions offered by 6ccvd.com.
Executive Summary
Section titled âExecutive Summaryâ- Core Achievement: Demonstration of a highly efficient, scalable spin-photon interface by coupling SnV- centers to one-dimensional photonic crystal cavities fabricated in MPCVD diamond.
- Performance Metrics: Achieved a 40-fold increase in SnV- emission intensity and a 10-fold reduction in excited-state lifetime, corresponding to an experimental Purcell factor (FP) of 25.
- Quantum Efficiency: Successfully channeled 90% (ÎČ factor) of the emitted photons into the cavity mode via the Zero-Phonon Line (ZPL), enabling a ZPL photon creation rate exceeding 1 GHz.
- Material Foundation: Fabrication relied on electronic-grade Single Crystal Diamond (SCD) combined with a Shallow Ion Implantation and Growth (SIIG) method, utilizing high-quality MPCVD diamond overgrowth (90 nm thick film).
- Device Structure: Nanophotonic resonators were fabricated using quasi-isotropic etching to create suspended diamond waveguides (300 nm width, 200 nm thickness) featuring a measured quality factor (Q) of 2135 ± 170.
- Scalability: The results validate SnV- centers integrated with nanocavities as a promising platform for quantum networks, offering long spin coherence times accessible at cryogenic temperatures above 1 K, without the need for dilution refrigerators.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental results:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Emission Intensity Enhancement | 40 ± 4 | Fold | C transition (619.6 nm) |
| Excited-State Lifetime Reduction | 10.1 ± 1.2 | Factor | On-resonance vs. Off-resonance |
| Experimental Purcell Factor (FPexp) | 24.8 ± 3.0 | N/A | Corrected for non-unity radiative probability |
| Photon Channeling Efficiency (ÎČ) | 90.1 ± 1.1 | % | Probability of decay into cavity mode via ZPL |
| ZPL Photon Creation Rate | > 1 | GHz | Result of high Purcell enhancement |
| Measured Cavity Quality Factor (Q) | 2135 ± 170 | N/A | Transmission measurement |
| Fitted Cavity Quality Factor (Q) | 2384 ± 366 | N/A | Lorentzian fit to decay rates |
| Cavity Resonance Wavelength (λres) | 619.656 ± 0.032 | nm | Center wavelength of Lorentzian fit |
| Operating Temperature | ~ 5 | K | Cryogenic characterization |
| Waveguide Thickness (h) | 200 | nm | Fabricated device dimension |
| Waveguide Width (w) | 300 | nm | Fabricated device dimension |
| Sn+ Implantation Energy | 1 | keV | Shallow Ion Implantation |
| Sn+ Implantation Dose | 5 x 1011 | cm-2 | SnV- center generation |
Key Methodologies
Section titled âKey MethodologiesâThe experiment relied on precise material preparation and advanced MPCVD growth techniques to integrate SnV- centers into nanophotonic structures.
- Substrate Preparation:
- Electronic-grade Single-Crystalline Diamond (SCD) plate used as the starting material.
- Chip cleaned via boiling tri-acid solution (sulfuric/nitric/perchloric acids).
- Top 500 nm of the chip removed via O2 plasma etch.
- Shallow Ion Implantation and Growth (SIIG):
- 120Sn+ ions implanted at low energy (1 keV) with a dose of 5 x 1011 cm-2.
- This process creates SnV centers at a shallow depth of approximately 90 nm.
- High-Quality MPCVD Overgrowth:
- A 90 nm thick film of high-quality diamond material was subsequently grown via Microwave Plasma Chemical Vapor Deposition (MPCVD).
- Recipe Parameters: H2 flow (300 sccm), CH4 flow (0.5 sccm), Stage Temperature (650° C), Microwave Power (1100 W), Pressure (23 Torr).
- Nanophotonic Fabrication (Quasi-Isotropic Etching):
- 200 nm of SixNy grown and patterned via electron-beam lithography.
- Diamond etched using anisotropic O2 RIE.
- Structures undercut using a high-temperature (300° C) quasi-isotropic O2 plasma etch to release the nanobeam waveguides.
- Device Characterization:
- Measurements conducted at cryogenic temperatures (~ 5 K).
- Cavity resonance wavelength tuned by injecting Argon gas into the cryostat (gas condensation red-shifts the mode).
- Time-resolved PL measurements used to quantify excited-state lifetime and Purcell enhancement.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful replication and extension of this high-impact quantum research require ultra-high-purity diamond materials and precise fabrication control, areas where 6CCVD excels.
| Applicable Materials & Service | 6CCVD Capability Mapping | Relevance to SnV- Research |
|---|---|---|
| Optical Grade SCD Substrates | Single Crystal Diamond (SCD) plates up to 500 ”m thick, and substrates up to 10 mm. Electronic-grade purity is standard. | Provides the low-strain, ultra-low nitrogen content necessary for stable, coherent Group-IV color centers (SnV-, SiV-) and achieving lifetime-limited linewidths. |
| Custom MPCVD Overgrowth | Custom Thickness and Recipe Control. We offer precise MPCVD growth services to replicate the 90 nm overgrowth layer used in the SIIG method (650° C, 1100 W). | Essential for healing implantation damage and ensuring the SnV- centers are embedded in high-quality diamond material, maximizing quantum efficiency. |
| High-Precision Polishing | Ultra-Smooth Polishing (Ra < 1 nm). Our SCD plates are polished to minimize surface roughness. | Critical for minimizing scattering losses in the nanophotonic structures, directly supporting the high Q factors (Q > 2000) required for strong Purcell enhancement (FP = 25). |
| Custom Dimensions & Etching Compatibility | Plates/Wafers up to 125 mm (PCD) and Custom SCD Sizes. We provide materials tailored for large-scale fabrication matrices and compatible with RIE and quasi-isotropic etching techniques. | Ensures material compatibility for scaling up the fabrication of large arrays of devices on a single chip, as demonstrated in the paper. |
| Integrated Metalization | In-House Metalization Services (Au, Pt, Pd, Ti, W, Cu). | Supports future device integration, such as creating electrical contacts for dynamic strain tuning or integrated microwave lines necessary for spin control and extended quantum networks. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in MPCVD diamond material science and can assist researchers in defining optimal material specifications (e.g., specific crystallographic orientation, surface termination, and thickness tolerances) required for similar SnV-/Group-IV Quantum Emitter projects. We ensure our materials are pre-qualified for advanced processing steps like shallow ion implantation and high-temperature etching.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
The realization of quantum networks critically depends on establishing\nefficient, coherent light-matter interfaces. Optically active spins in diamond\nhave emerged as promising quantum nodes based on their spin-selective optical\ntransitions, long-lived spin ground states, and potential for integration with\nnanophotonics. Tin-vacancy (SnV$^{\,\textrm{-}}$) centers in diamond are of\nparticular interest because they exhibit narrow-linewidth emission in\nnanostructures and possess long spin coherence times at temperatures above 1 K.\nHowever, a nanophotonic interface for SnV$^{\,\textrm{-}}$ centers has not yet\nbeen realized. Here, we report cavity enhancement of the emission of\nSnV$^{\,\textrm{-}}$ centers in diamond. We integrate SnV$^{\,\textrm{-}}$\ncenters into one-dimensional photonic crystal resonators and observe a 40-fold\nincrease in emission intensity. The Purcell factor of the coupled system is 25,\nresulting in channeling of the majority of photons ($90\%$) into the cavity\nmode. Our results pave the way for the creation of efficient, scalable\nspin-photon interfaces based on SnV$^{\,\textrm{-}}$ centers in diamond.\n