Diamond Nitrogen-vacancy Centers and Development to Laser Science

At a Glance

Metadata	Details
Publication Date	2020-01-01
Journal	The Review of Laser Engineering
Authors	Muneaki Hase
Institutions	University of Tsukuba
Analysis	Full AI Review Included

6CCVD Technical Analysis: Diamond NV Centers and Nonlinear Laser Science

This documentation analyzes the key technical requirements and findings presented in the research paper regarding the development of Nitrogen-Vacancy (NV) centers in diamond for nonlinear optical applications, and correlates them directly with 6CCVD’s superior MPCVD diamond material offerings.

Executive Summary

The research details the enhanced nonlinear optical effects—specifically the Optical Kerr Effect (OKE) and Two-Photon Absorption (TPA)—achieved by incorporating Nitrogen-Vacancy (NV) centers into single crystal diamond (SCD) using femtosecond (fs) laser excitation.

Core Achievement: Introduction of NV centers significantly enhances nonlinear optical susceptibility, demonstrated by a notable increase in the nonlinear refractive index (n₂) and the TPA coefficient (β).
Material Enhancement: The nonlinear refractive index (n₂) was found to increase by more than an order of magnitude in highly implanted diamond compared to non-implanted SCD.
Nonlinear Mechanism: Increased enhancement is attributed to NV- states initiating Two-Photon Absorption (TPA), which is highly relevant for ultrafast optical switching and modulation applications.
Performance Metrics: The resulting Figure of Merit (FOM = 2βλ/n₂) reached approximately 4.7 for the high-dose sample, making NV-doped diamond competitive with established nonlinear materials like amorphous silicon (FOM ≈ 3.0).
Methodology: NV centers were successfully created using controlled N⁺ ion implantation followed by annealing, utilizing high-purity SCD substrates.
Commercial Relevance: This work paves the way for high-speed, high-sensitivity quantum sensing and optical modulation techniques utilizing the fast dynamics inherent in fs laser-induced nonlinear effects.

Technical Specifications

The following table extracts critical hard data, derived parameters, and experimental conditions from the research paper, focusing on the nonlinear optical performance of the modified SCD.

Parameter	Value	Unit	Context
Laser Wavelength	800	nm	Femtosecond pulse center wavelength
Laser Pulse Width	40	fs	Used for ultrafast measurements
Repetition Rate	100	kHz	Used for Z-scan and Pump-Probe experiments
Substrate Material	High-purity	SCD	Base material for NV creation (Type-IIa equivalent)
Max Implantation Dose	1.0 x 10¹²	N⁺/cm²	Highest dose sample (Sample 3)
Ion Acceleration Voltage	30	keV	Used for N⁺ implantation
Implantation Depth	~50	nm	Calculated surface layer depth
Peak Nonlinear Index (n₂)	24.2 x 10^-20	m²/W	Observed in Sample 3
Peak TPA Coefficient (β)	1.75 x 10^-1	cm/GW	Observed in Sample 2
Figure of Merit (FOM)	~4.7	N/A	Calculated for Sample 3, high performance
NV Ground State Splitting	2.87	GHz	Characteristic triplet state transition
NV- ZPL (Zero Phonon Line)	637	nm	Characteristic optical emission

Key Methodologies

The research successfully leveraged controlled material engineering techniques essential for creating and characterizing high-quality NV centers in diamond for nonlinear optics.

Substrate Preparation: High-purity, intrinsic single crystal diamond (SCD) substrates were chosen to minimize background impurities and maximize the control over induced NV center concentration.
NV Center Generation (Standard Method): Nitrogen-Vacancy (NV) centers were generated by precise N⁺ ion implantation at controlled dose levels (ranging from 10¹¹ to 10¹² N⁺/cm²) to introduce nitrogen atoms into the lattice.
Defect Engineering: Subsequent high-temperature annealing was applied to mobilize native and introduced vacancies (V), allowing them to trap implanted nitrogen atoms (N), thus forming the desired NV centers (N-V complexes).
Ultrafast Excitation: The samples were excited using a femtosecond (fs) laser system (800 nm center wavelength) to probe the purely nonlinear third-order optical effects (OKE and TPA), which occur on extremely fast time scales.
Nonlinear Characterization: The Closed-aperture Z-scan technique was employed to measure the change in transmittance as a function of the sample position relative to the laser focus, allowing for the precise extraction of the nonlinear refractive index (n₂) and Two-Photon Absorption coefficient (β).
Dynamic Analysis: Pump-Probe Reflectivity measurements provided temporal resolution for the nonlinear response, confirming the fast-carrier dynamics associated with the NV center-induced absorption.

6CCVD Solutions & Capabilities

6CCVD is uniquely positioned to supply the advanced MPCVD diamond materials required to replicate, scale, and extend this critical research into deployable quantum and ultrafast photonic devices. Our capabilities ensure the high purity, low defect density, and geometric precision essential for high-performance nonlinear optics.

Applicable Materials

To achieve high-fidelity NV center research using controlled implantation or in-situ doping, the highest quality diamond is mandatory.

Research Requirement	6CCVD Optimized Solution	Core Material Property
High Purity Base	Optical Grade SCD (Single Crystal Diamond)	Extremely low native nitrogen concentration (< 1 ppb), guaranteeing that all measured nonlinear effects are dominated by intentionally engineered NV centers.
High-Density Doping	Nitrogen-Doped SCD (N-doped SCD)	For researchers exploring in-situ NV generation during growth, 6CCVD offers custom-doped SCD layers with highly uniform nitrogen concentration control.
Ultrafast Switching/Sensing	Polycrystalline Diamond (PCD) Wafers	Available for large-area, cost-effective industrial scaling of ultrafast photonic components, with plates up to 125mm in diameter.

Customization Potential

The success of these experiments relies on precise material dimensions, surface finishing, and potential integration with electronic structures (as suggested by mentions of ODMR and p-i-n diodes). 6CCVD offers comprehensive services to support these complex needs.

Customization Service	Relevance to NV Center Research	6CCVD Capability Specification
Precision Polishing	Essential for minimizing light scattering and achieving high signal-to-noise ratio in Z-scan and Pump-Probe reflectivity experiments.	SCD: Ra < 1 nm (Ultra-smooth surface finish).
Custom Thickness Control	Required for matching active layer depth (e.g., 50 nm implantation) to the bulk substrate.	SCD/PCD: Thicknesses precisely grown from 0.1 µm up to 500 µm.
Advanced Metalization	Necessary for integrating microwave transmission lines for ODMR (Optically Detected Magnetic Resonance) or creating diode structures.	Internal Metalization: Custom deposition and patterning of Au, Pt, Pd, Ti, W, and Cu contact layers.
Large Area Substrates	Enables scaling from research samples to integrated photonic chips.	PCD Wafers: Available in custom dimensions up to 125 mm.
Crystallographic Alignment	Critical for optimal NV alignment and maximal optical coherence time.	Substrates provided with precision orientation (e.g., [100], [111]).

Engineering Support

This research demonstrates the transition of NV centers from pure quantum sensing to integrated nonlinear quantum photonics. 6CCVD’s in-house team of material scientists and PhD engineers are prepared to assist in:

Material Selection: Guiding researchers on the optimal choice between Optical Grade SCD (for low background noise) or specific N-doped SCD (for controlled in-situ growth).
Substrate Optimization: Providing pre-implantation optimized substrates that ensure minimal surface damage and maximum post-annealing NV yield.
Device Integration: Consulting on suitable metal stack recipes and polishing specifications for fabricating micro-wave antennas and integrated optical components for ultrafast Nonlinear Quantum Sensing projects.
Global Logistics: Ensuring efficient and secure global shipping (DDU default, DDP available) to research facilities worldwide.

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

View Original Abstract

Nitrogen-vacancy (NV) center in diamond crystals offers high spatial-resolution quantum sensing based on controllable photo-luminescence under microwave irradiation. In order to explore possible development of NV centers toward nonlinear quantum sensing, we investigate the effect of NV centers in single crystal diamond on nonlinear optical effects using 40 fs femtosecond laser pulses. The near-infrared femtosecond pulses allow us to study purely nonlinear optical effects, such as optical Kerr effect (OKE) and two-photon absorption (TPA). We found that both nonlinear optical effects are significantly enhanced by the introduction of NV centers. In particular, our data demonstrate that the OKE signal is strongly enhanced for the heavily implanted type-IIa diamond, being possibly originated from cascading OKE, where the high-density NV centers break the spatial inversion symmetry near the surface region of diamond.

Tech Support

Original Source

DOI: https://doi.org/10.2184/lsj.48.8_436