NV– diamond laser

At a Glance

Metadata	Details
Publication Date	2021-12-08
Journal	Nature Communications
Authors	Alexander Savvin, A. E. Dormidonov, Evgeniya Smetanina, V. P. Mitrokhin, E. I. Lipatov
Institutions	National Research Tomsk State University, All Russia Research Institute of Automatics
Citations	70
Analysis	Full AI Review Included

Technical Documentation & Sales Analysis: NV^- Diamond Laser

Executive Summary

This study successfully demonstrates, for the first time, laser generation originating from negatively charged Nitrogen-Vacancy (NV^-) color centers in an optically pumped diamond crystal. This breakthrough validates diamond’s potential as a highly robust, tunable, solid-state active medium, crucial for advancing near-infrared (NIR) laser systems and quantum technologies.

Core Achievement: Stable lasing was achieved at a central wavelength of 720 nm, utilizing NV^- centers as the gain medium.
Performance Metrics: Lasing pulses demonstrated a minimal duration of ~1 ns, a total energy of approximately 10 nJ, and a spectral width narrowing to 20 nm.
Material Criticality: Stable lasing requires an optimal concentration of NV^- centers (calculated at ~2.5 x 10¹⁷ cm^-3) within the diamond host, necessitating precise control over initial nitrogen doping and post-processing (irradiation/annealing).
Methodology: A direct pump-probe scheme using a picosecond 532 nm pump pulse train was employed to investigate gain dynamics, confirming a maximum achieved gain coefficient of 1.5 cm^-1.
Scaling Opportunity: While the study used HPHT diamond, its size limitations restrict high-power scaling. MPCVD diamond (6CCVD’s specialty) offers superior control, high purity, and large-area substrates necessary for industrial and CW laser development.
Future Direction: The research paves the way for high-power CW and ultrashort pulse lasers based on the NV^- diamond active medium, leveraging diamond’s unique thermal and mechanical properties.

Technical Specifications

Extracted parameters relating to the diamond material, experimental conditions, and achieved laser performance.

Parameter	Value	Unit	Context
Diamond Sample Source	HPHT Type IIa	N/A	Material investigated in the study
Sample Plate Dimensions	4 x 3 x 0.25	mm	Physical dimensions of the active medium
Critical NV^- Concentration	~2.5 x 10¹⁷ (1.4)	cm^-3 (ppm)	Minimum concentration required for stable lasing (Zone S2)
Nitrogen Concentration (S2)	3.1 x 10¹⁹ (175)	cm^-3 (ppm)	Total nitrogen required for NV^- formation
Electron Irradiation Dose	1-10¹⁸	e^-/cm²	Required treatment for vacancy creation
Annealing Temperature	800	°C	Required post-growth annealing (24 h vacuum)
Pump Wavelength	532	nm	Picosecond Nd:YAG laser
Pump Pulse Duration	150	ps	Individual pulse length
Maximum Achieved Gain	1.5	cm^-1	Gain coefficient sufficient for stable lasing
Lasing Output Wavelength	720	nm	Center wavelength of the laser pulse spectrum
Lasing Pulse Duration	~1	ns	Minimal FWHM achieved
Lasing Pulse Energy (Max)	10.4	nJ	Total energy from two output couplers
Resonator Mirror Reflectivity	95	%	Reflectivity range 700 to 750 nm

Key Methodologies

The experiment relied on specific material preparation steps (defect engineering) and a precision pump-probe setup to analyze and achieve stimulated emission.

Material Growth & Preparation: HPHT diamond (4 x 3 x 0.25 mm) was grown with two distinct zones (S1: low N, S2: high N).
Defect Engineering: The diamond was irradiated with 3 MeV electrons (1-10¹⁸ e^-/cm²) to create vacancies, followed by high-temperature annealing (800 °C for 24 h in vacuum) to mobilize vacancies and form NV complexes.
Cross-Section Determination: Emission (σ_em) and absorption (σ_abs) cross-sections were calculated based on photoluminescence and absorption spectra, determining the target NV^- concentration (~2.5 x 10¹⁷ cm^-3) in the active S2 zone.
Pump Source: A train of 150-ps, 532 nm Nd:YAG laser pulses (delayed by 4.4 ns) was used for optical pumping, leveraging high temporal regularity and shot-to-shot repeatability.
Stimulated Emission Registration: A direct pump-probe method was implemented using a 675 nm CW laser diode as the probe beam, positioned in either transverse or longitudinal configuration.
Resonator Configuration: Lasing was achieved using a cavity consisting of two 95% reflection flat mirrors, a 15 mm BK7 spherical lens, and the diamond sample aligned at the Brewster’s angle to promote lasing along the material.

6CCVD Solutions & Capabilities

6CCVD provides the specialized CVD diamond substrates and material processing expertise required to replicate, scale, and optimize this groundbreaking NV^- laser technology. The limitations imposed by using small, non-optimized HPHT crystals can be overcome by leveraging 6CCVD’s advanced MPCVD growth control.

Applicable Materials

To achieve the precise nitrogen incorporation and optical quality demonstrated in the research, 6CCVD recommends:

6CCVD Material	Key Feature Alignment with Research Needs
Optical Grade SCD	Essential for minimizing scattering losses (absorption coefficient of S2 zone reached 14 cm^-1). Our SCD ensures superior purity and low birefringence.
SCD with Controlled N Doping	MPCVD allows for precise, uniform nitrogen incorporation to reach the target NV^- concentration (~2.5 x 10¹⁷ cm^-3 or 1.4 ppm) in larger volumes, exceeding the capabilities of small HPHT zones.
SCD Substrates (Thick)	We can supply substrates up to 10 mm thick, which allows for significantly increased active gain length compared to the 0.25 mm plate used in the paper, leading to higher output energy.

Customization Potential

The success of the NV^- diamond laser depends critically on material geometry and post-processing alignment. 6CCVD provides end-to-end customization to meet these precise requirements:

Custom Dimensions and Thickness: While the paper used a small 4 x 3 mm plate, 6CCVD can produce Single Crystal Diamond (SCD) up to 15x15 mm and Polycrystalline Diamond (PCD) up to 125 mm diameter.
Precision Polishing & Geometry: The material used required polishing at Brewster’s angle (67.5°) for longitudinal lasing. 6CCVD offers high-precision polishing (Ra < 1 nm for SCD) and custom laser cutting services to ensure exact geometric alignment for maximum gain.
Post-Growth Defect Engineering: 6CCVD works with established partners to provide necessary post-growth treatments:
- High-Energy Electron/Ion Irradiation: To create the required high density of vacancies (e.g., 1-10¹⁸ e^-/cm² dose).
- High-Temperature Annealing: Controlled vacuum annealing (e.g., 800 °C for 24 h) to ensure efficient NV complex formation and optimization of the NV^-/NV⁰ ratio.

Engineering Support & Scaling

The study notes that achieving CW lasing requires carefully controlling the gain and induced losses ratio, which is limited by NV^- ionization under high-power pumping. 6CCVD’s expertise directly addresses this scaling challenge:

Thermal Management: Diamond’s superior thermal conductivity is key for high-power CW operation. Our Optical Grade SCD minimizes thermal lensing and fracture risk, necessary to move beyond pulsed experiments.
Advanced Defect Control: 6CCVD’s in-house PhD team specializes in nitrogen defect engineering using MPCVD to optimize the concentration profile (N concentration of 3.1 x 10¹⁹ cm^-3 was required here). We assist clients in designing material recipes that minimize NV⁰ formation and maximize stable NV^- population.
Global Logistics: We provide global shipping (DDU default, DDP available), ensuring sensitive optical materials reach your lab or fabrication facility efficiently and securely worldwide.

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