Optically detected magnetic resonance of high-density ensemble of NV−centers in diamond

At a Glance

Metadata	Details
Publication Date	2016-05-23
Journal	Journal of Physics Condensed Matter
Authors	Yuichiro Matsuzaki, Hiroki Morishita, Takaaki Shimo-Oka, Toshiyuki Tashima, Kosuke Kakuyanagi
Institutions	National Institute of Information and Communications Technology, The University of Osaka
Citations	47
Analysis	Full AI Review Included

Technical Documentation & Analysis: High-Density NV^- Ensembles in MPCVD Diamond

This document analyzes the research paper, “Optically detected magnetic resonance of high-density ensemble of NV^- centers in diamond” (arXiv:1508.04501v1), focusing on material requirements and alignment with 6CCVD’s advanced MPCVD diamond capabilities.

Executive Summary

The reported research establishes a crucial theoretical framework for understanding and utilizing high-density Nitrogen-Vacancy (NV^-) ensembles in diamond, essential for next-generation quantum technologies.

Core Achievement: Successful modeling of Optically Detected Magnetic Resonance (ODMR) spectra in high-density NV^- ensembles, including reproduction of the highly sensitive sharp dip around 2870 MHz.
Key Physics: The sharp ODMR feature is demonstrated to be highly sensitive to homogeneous broadening (Γ_b), allowing accurate estimation of this key coherence parameter, even in the presence of strain and inhomogeneous magnetic fields.
Material Requirement: The entire study relies on high-quality diamond samples containing high concentrations (up to 5 x 10¹⁸ cm^-3) of engineered NV^- centers.
Strategic Application: This method provides an efficient tool to characterize ensemble parameters (strain, field inhomogeneity, broadening), which is crucial for realizing practical diamond-based quantum information processing and long-lived quantum memory devices.
6CCVD Value Proposition: 6CCVD delivers custom, highly controlled MPCVD Single Crystal Diamond (SCD) or Polycrystalline Diamond (PCD) required for precise NV ensemble engineering, offering specific nitrogen doping, orientations, and superior surface preparation.

Technical Specifications

The following table extracts the critical hard data points and parameters used in the experimental setup and numerical modeling:

Parameter	Value	Unit	Context
NV Ensemble Density	Up to 5 x 10¹⁸	cm^-3	Required for observing high-density ensemble effects
Sharp Dip Frequency (B=0)	2870	MHz	Resonance frequency for zero applied magnetic field
Applied Magnetic Fields (B)	0, 1, 2	mT	Applied along the [111] crystallographic axis
Homogeneous Width (Γ_b/2π)	0.3	MHz	Critical parameter for fitting the sharp ODMR dip
Inhomogeneous Field Width (HWHM)	1.96	MHz	Parameter δ(gµ_BB_z)/2π from fitting
Inhomogeneous Strain Width (HWHM)	0.73	MHz	Parameter δE₁/2π = δE₂/2π from fitting
Nitrogen Hyperfine Coupling	2 x 2.3	MHz	Used in numerical simulation model
Coherence Property	Long coherence time (up to seconds)	second	Fundamental NV^- property enabling quantum applications
Crystal Orientation	[111]	Axis	Alignment direction for applied magnetic field

Key Methodologies

The research relies on precise material engineering and advanced spectroscopic techniques suitable for high-density NV^- ensembles:

Sample Preparation (NV Creation): NV centers were created using ion implantation (C¹²+ and N¹⁵) followed by subsequent high-temperature annealing. This methodology is necessary to achieve the high density of NV centers required for ensemble characterization.
Experimental Setup: Measurements were conducted using a confocal microscope setup optimized for ODMR.
ODMR Technique: NV^- centers were detected optically (fluorescence intensity change) after the application of microwave pulses, revealing the energy structure of the ground-state manifold.
Field Application: External magnetic fields (0 to 2 mT) were precisely applied and aligned along the NV axis ([111] direction) to separate and investigate the two exited spin states (|+1> and |-1>).
Modeling Approach: The experimental ODMR spectra were reproduced using a theoretical model that explicitly incorporates the spin-1 properties of the NV^- center, alongside inhomogeneous magnetic fields, strain distributions, and homogeneous broadening (Γ_b).

6CCVD Solutions & Capabilities

Replication and extension of this crucial quantum research demand highly controlled MPCVD diamond. 6CCVD’s manufacturing expertise directly addresses the specific material requirements for high-density NV ensemble engineering:

Applicable Materials

The high NV density (up to 5 x 10¹⁸ cm^-3) used in this work requires precise control over nitrogen content during or after growth.

Research Requirement	6CCVD Material Solution	Customization & Specification
High NV Density Target	High-Nitrogen SCD (Single Crystal Diamond)	Nitrogen content tailored during growth for high substitutional N concentration, suitable for post-growth NV formation (via implantation/annealing).
Wafer Availability	High-Quality Polycrystalline Diamond (PCD)	Available in large plates/wafers up to 125mm in size, supporting ensemble research scale-up.
Crystallographic Alignment	SCD Substrates with Controlled Orientation	We supply SCD plates with precise orientation control, including the required [111] alignment, critical for accurate magnetic field studies.
Optical Access	Optical Grade SCD/PCD	High-purity, low-birefringence material is essential for effective Optically Detected Magnetic Resonance (ODMR) experiments.

Customization Potential

6CCVD offers comprehensive engineering services vital for high-precision quantum research:

Precision Polishing: ODMR requires excellent optical access. We provide super-polished SCD surfaces (Ra < 1nm) and high-quality polishing for inch-size PCD (Ra < 5nm), minimizing light scattering and maximizing signal detection efficiency.
Custom Dimensions: While the paper implies small samples for confocal microscopy, we offer custom plates and wafers up to 125mm to support large-scale device integration or multiple simultaneous experiments.
Advanced Fabrication: 6CCVD provides laser cutting and shaping services to create microstructures or specific geometries necessary for integration into complex quantum systems (e.g., coupling to microwave circuits or superconducting systems).
Metalization Services: Although not explicitly focused on in the text, the application of precise microwave pulses often requires integrated electrodes or waveguides. 6CCVD offers in-house metalization capabilities (Au, Pt, Pd, Ti, W, Cu) for contact fabrication.

Engineering Support

Understanding the complex interplay between strain, magnetic field inhomogeneity, and homogeneous broadening is critical for developing high-coherence NV-based devices.

6CCVD’s in-house PhD engineering team can assist researchers with material selection, doping strategies, and post-processing methods tailored specifically for high-density NV ensemble projects related to Quantum Information Processing and Quantum Metrology. We ensure material properties maximize the yield and coherence necessary for replicating or extending the results presented in this paper.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Optically detected magnetic resonance (ODMR) is a way to characterize the ensemble of NV-centers. Recently, a remarkably sharp dip was observed in the ODMR with a high-density ensemble of NV centers. The model (Zhu et al 2014 Nat. Commun. 5 3424) indicated that such a dip was due to the spin-1 properties of the NV- centers. Here, we present many more details of the analysis to show how this model can be applied to investigate the properties of the NV- centers. By using our model, we have reproduced the ODMR with and without applied external magnetic fields. Additionally, we investigate how the ODMR is affected by the typical parameters of the ensemble NV- centers such as strain distributions, inhomogeneous magnetic fields, and homogeneous broadening width. Our model provides a way to characterize the NV- center from the ODMR, which would be crucial to realize diamond-based quantum information processing.

Tech Support

Original Source

DOI: https://doi.org/10.1088/0953-8984/28/27/275302