Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of the Optical Society of America B

Measuring the number of (N-V)^− centers in single fluorescent nanodiamonds in the presence of quenching effects

Lun-Hsuan Chen, Tsong‐Shin Lim, Huan‐Cheng Chang

Published Aug 3, 2012• 9 citations
Publisher

Abstract

Quenching effects, including graphite-shell quenching and impurity quenching, on negatively charged nitrogen-vacancy (N-V)− centers in fluorescent nanodiamonds (FNDs) can reduce the fluorescence quantum yield and bring about multiexponential decay fluorescence to FNDs. This causes the number of (N-V)− centers to be underestimated when using the photon correlation method, which presumes identical emitters. This study proposes a method that combines time-resolved spectroscopy and photon correlation spectroscopy to modify the number measurement with the photon correlation method. The average number of (N-V)− centers in 35 nm FNDs was corrected from 7.6 with the unmodified method to 11.96 with the modified method.

DOI
10.1364/josab.29.002309

Related papers

Quantifying the number of color centers in single fluorescent nanodiamonds by photon correlation spectroscopy and Monte Carlo simulation

Yuen Yung Hui, Yi-Ren Chang, Tsong‐Shin Lim +3 more

The number of negatively charged nitrogen-vacancy centers (N-V)− in fluorescent nanodiamond (FND) has been determined by photon correlation spectroscopy and Monte Carlo simulations at the single particle level. By taking account of the random dipole orientation of the multiple (N-V)− fluorophores and simulating the probability distribution of their effective numbers (Ne), we found that the actual number (Na) of the fluorophores is in linear correlation with Ne, with correction factors of 1.8 and 1.2 in measurements using linearly and circularly polarized lights, respectively. We determined Na=8±1 for 28 nm FND particles prepared by 3 MeV proton irradiation.

Applied Physics Letters•Jan 5, 2009•27 citations

The properties of the nitrogen-vacancy center in milled chemical vapor deposition nanodiamonds

Alessandro Mameli, Giannis Thalassinos, Marco Capelli +14 more

Abstract Fluorescent nanodiamonds (FNDs) containing negatively charged nitrogen-vacancy (NV − ) centers are vital for many emerging quantum sensing applications from magnetometry to intracellular sensing in biology. However, developing a scalable fabrication method for FNDs hosting color centers with consistent bulk-like photoluminescence (PL) and spin coherence properties remains a highly desired but unrealized goal. Here, we investigate optimized ball milling of single-crystal diamonds produced via chemical vapor deposition (CVD) and containing 2 ppm of substitutional nitrogen and 0.3 ppm of NV − to achieve this goal. The NV charge state, PL lifetime, and spin properties of bulk CVD diamond samples are directly compared to milled CVD FNDs and commercial high-pressure high-temperature (HPHT) FNDs. We find that on average, the relative contribution of the NV − charge state to the total NV PL is lower and the NV PL lifetime is longer in CVD FNDs compared to HPHT FNDs, both likely due to the lower N s 0 concentration in CVD FNDs. The CVD bulk and CVD FNDs on average show similar average T 1 spin relaxation times of 3.2 ± 0.7 ms and 4.7 ± 1.6 ms, respectively, compared to 0.17 ± 0.01 ms for commercial HPHT FNDs. Our results demonstrate that ball milling of CVD diamonds enables the large-scale fabrication of NV ensembles in FNDs with bulk-like T 1 spin relaxation properties.

Materials for Quantum Technology•Feb 12, 2026•4 citations

The properties of the nitrogen-vacancy center in milled chemical vapor deposition nanodiamonds

Mameli, Alessandro, Giannis Thalassinos, Marco Capelli +14 more

Fluorescent nanodiamonds (FNDs) containing negatively charged nitrogen-vacancy (NV-) centers are vital for many emerging quantum sensing applications from magnetometry to intracellular sensing in biology. However, developing a scalable fabrication method for FNDs hosting color centers with consistent bulk-like photoluminescence (PL) and spin coherence properties remains a highly desired but unrealized goal. Here, we investigate optimized ball milling of single-crystal diamonds produced via chemical vapor deposition (CVD) and containing 2 ppm of substitutional nitrogen and 0.3 ppm of NV- to achieve this goal. The NV charge state, PL lifetime, and spin properties of bulk CVD diamond samples are directly compared to milled CVD FNDs and commercial high-pressure high-temperature (HPHT) FNDs. We find that on average, the relative contribution of the NV- charge state to the total NV PL is lower and the NV PL lifetime is longer in CVD FNDs compared to HPHT FNDs, both likely due to the lower Ns0 concentration in CVD FNDs. The CVD bulk and CVD FNDs on average show similar average T1 spin relaxation times of 3.2 $\pm$ 0.7 ms and 4.7 $\pm$ 1.6 ms, respectively, compared to 0.17 $\pm$ 0.01 ms for commercial HPHT FNDs. Our results demonstrate that ball milling of CVD diamonds enables the large-scale fabrication of NV ensembles in FNDs with bulk-like T1 spin relaxation properties.

arXiv:2508.13725•Aug 1, 2025•0 citations

Monitoring Dark-State Dynamics of a Single Nitrogen-Vacancy Center in Nanodiamond by Auto-Correlation Spectroscopy: Photonionization and Recharging

Mengdi Zhang, Bai‐Yan Li, Jing Liu

In this letter, the photon-induced charge conversion dynamics of a single Nitrogen-Vacancy (NV) center in nanodiamond between two charge states, negative (NV−) and neutral (NV0), is studied by the auto-correlation function. It is observed that the ionization of NV− converts to NV0, which is regarded as the dark state of the NV−, leading to fluorescence intermittency in single NV centers. A new method, based on the auto-correlation calculation of the time-course fluorescence intensity from NV centers, was developed to quantify the transition kinetics and yielded the calculation of transition rates from NV− to NV0 (ionization) and from NV0 to NV− (recharging). Based on our experimental investigation, we found that the NV−-NV0 transition is wavelength-dependent, and more frequent transitions were observed when short-wavelength illumination was used. From the analysis of the auto-correlation curve, it is found that the transition time of NV− to NV0 (ionization) is around 0.1 μs, but the transition time of NV0 to NV− (recharging) is around 20 ms. Power-dependent measurements reveal that the ionization rate increases linearly with the laser power, while the recharging rate has a quadratic increase with the laser power. This difference suggests that the ionization in the NV center is a one-photon process, while the recharging of NV0 to NV− is a two-photon process. This work, which offers theoretical and experimental explanations of the emission property of a single NV center, is expected to help the utilization of the NV center for quantum information science, quantum communication, and quantum bioimaging.

Nanomaterials•Apr 10, 2021•3 citations

Long Spin Relaxation Times in CVD-Grown Nanodiamonds

Jeroen Prooth, Michael Petrov, Alevtina Shmakova +5 more

Currently, the primary applications of fluorescent nanodiamonds (FNDs) are in the area of biosensing, by using photoluminescence or spin properties of colour centres, mainly represented by the Nitrogen Vacancy (NV) point defect. The sensitivity of NV-FNDs to external fields is, however, limited by crystallographic defects, which influence their key quantum state characteristics - the spin longitudinal (\textit{T$_1$}) and spin transversal (\textit{T$_2$}) relaxation and coherence times, respectively. We report on utilising an advanced FND growth technique consisting of heterogeneous nucleation on pre-engineered sites to create FNDs averaging around 60 nm in size, with mean longitudinal coherence times of 800 $μ$s and a maximum over 1.8 ms, close to bulk theoretical values. This is a major, nearly ten-fold improvement over commercially available nanodiamonds for the same size range of 50 to 150 nm. Heavy-N doped nanodiamond shells, important for sensing events in nm proximity to the diamond surface, are fabricated and discussed in terms of re-nucleation and twinning on \{111\} crystal facets. We also discuss scalability issues in order to enable the production of FND volumes matching the needs of sensing applications.

cond-mat.mes-hallCross-listedarXiv:2605.16394•Advanced Quantum Technologies•May 13, 2026•13 citations

Spin-dependent charge state interconversion of nitrogen vacancy centers in nanodiamonds

Reece P. Roberts, Mathieu L. Juan, Gabriel Molina‐Terriza

The nitrogen vacancy (NV) center in diamond is the most widely studied color center in diamond for its wide range of applications in both physics and biology. The negatively charged state ${\mathrm{NV}}^{\ensuremath{-}}$ is often favored for its better spin-optical properties, whereas the presence of the neutral charge state ${\mathrm{NV}}^{0}$ is often minimized or neglected by using a single optimized excitation wavelength. In many cases, the use of additional laser wavelengths has an important impact on the NV optical properties and can lead to a dramatically quenched fluorescence. Through measurements of the photophysics of the NV center we show in this work that this quenching mechanism is mediated by charge state interconversion providing additional channels for nonradiative decay. Our results show that this mechanism is also sensitive to the spin state of the ${\mathrm{NV}}^{\ensuremath{-}}$. A better understanding of this physical mechanism will help mitigate the spin and charge state depolarization effects that are detrimental for quantum technology applications.

Physical review. B./Physical review. B•May 17, 2019•23 citations
Quenching effects, including graphite-shell quenching and impurity quenching, on negatively charged nitrogen-vacancy (N-V)− centers in fluorescent nanodiamonds (FNDs) can reduce the fluorescence quantum yield and bring about multiexponential decay fluorescence to FNDs. This causes the number of (N-V)− centers to be underestimated when using the photon correlation method, which presumes identical emitters. This study proposes a method that combines time-resolved spectroscopy and photon correlation spectroscopy to modify the number measurement with the photon correlation method. The average number of (N-V)− centers in 35 nm FNDs was corrected from 7.6 with the unmodified method to 11.96 with the modified method.
The number of negatively charged nitrogen-vacancy centers (N-V)− in fluorescent nanodiamond (FND) has been determined by photon correlation spectroscopy and Monte Carlo simulations at the single particle level. By taking account of the random dipole orientation of the multiple (N-V)− fluorophores and simulating the probability distribution of their effective numbers (Ne), we found that the actual number (Na) of the fluorophores is in linear correlation with Ne, with correction factors of 1.8 and 1.2 in measurements using linearly and circularly polarized lights, respectively. We determined Na=8±1 for 28 nm FND particles prepared by 3 MeV proton irradiation.
Abstract Fluorescent nanodiamonds (FNDs) containing negatively charged nitrogen-vacancy (NV − ) centers are vital for many emerging quantum sensing applications from magnetometry to intracellular sensing in biology. However, developing a scalable fabrication method for FNDs hosting color centers with consistent bulk-like photoluminescence (PL) and spin coherence properties remains a highly desired but unrealized goal. Here, we investigate optimized ball milling of single-crystal diamonds produced via chemical vapor deposition (CVD) and containing 2 ppm of substitutional nitrogen and 0.3 ppm of NV − to achieve this goal. The NV charge state, PL lifetime, and spin properties of bulk CVD diamond samples are directly compared to milled CVD FNDs and commercial high-pressure high-temperature (HPHT) FNDs. We find that on average, the relative contribution of the NV − charge state to the total NV PL is lower and the NV PL lifetime is longer in CVD FNDs compared to HPHT FNDs, both likely due to the lower N s 0 concentration in CVD FNDs. The CVD bulk and CVD FNDs on average show similar average T 1 spin relaxation times of 3.2 ± 0.7 ms and 4.7 ± 1.6 ms, respectively, compared to 0.17 ± 0.01 ms for commercial HPHT FNDs. Our results demonstrate that ball milling of CVD diamonds enables the large-scale fabrication of NV ensembles in FNDs with bulk-like T 1 spin relaxation properties.
Fluorescent nanodiamonds (FNDs) containing negatively charged nitrogen-vacancy (NV-) centers are vital for many emerging quantum sensing applications from magnetometry to intracellular sensing in biology. However, developing a scalable fabrication method for FNDs hosting color centers with consistent bulk-like photoluminescence (PL) and spin coherence properties remains a highly desired but unrealized goal. Here, we investigate optimized ball milling of single-crystal diamonds produced via chemical vapor deposition (CVD) and containing 2 ppm of substitutional nitrogen and 0.3 ppm of NV- to achieve this goal. The NV charge state, PL lifetime, and spin properties of bulk CVD diamond samples are directly compared to milled CVD FNDs and commercial high-pressure high-temperature (HPHT) FNDs. We find that on average, the relative contribution of the NV- charge state to the total NV PL is lower and the NV PL lifetime is longer in CVD FNDs compared to HPHT FNDs, both likely due to the lower Ns0 concentration in CVD FNDs. The CVD bulk and CVD FNDs on average show similar average T1 spin relaxation times of 3.2 ±\pm± 0.7 ms and 4.7 ±\pm± 1.6 ms, respectively, compared to 0.17 ±\pm± 0.01 ms for commercial HPHT FNDs. Our results demonstrate that ball milling of CVD diamonds enables the large-scale fabrication of NV ensembles in FNDs with bulk-like T1 spin relaxation properties.
In this letter, the photon-induced charge conversion dynamics of a single Nitrogen-Vacancy (NV) center in nanodiamond between two charge states, negative (NV−) and neutral (NV0), is studied by the auto-correlation function. It is observed that the ionization of NV− converts to NV0, which is regarded as the dark state of the NV−, leading to fluorescence intermittency in single NV centers. A new method, based on the auto-correlation calculation of the time-course fluorescence intensity from NV centers, was developed to quantify the transition kinetics and yielded the calculation of transition rates from NV− to NV0 (ionization) and from NV0 to NV− (recharging). Based on our experimental investigation, we found that the NV−-NV0 transition is wavelength-dependent, and more frequent transitions were observed when short-wavelength illumination was used. From the analysis of the auto-correlation curve, it is found that the transition time of NV− to NV0 (ionization) is around 0.1 μs, but the transition time of NV0 to NV− (recharging) is around 20 ms. Power-dependent measurements reveal that the ionization rate increases linearly with the laser power, while the recharging rate has a quadratic increase with the laser power. This difference suggests that the ionization in the NV center is a one-photon process, while the recharging of NV0 to NV− is a two-photon process. This work, which offers theoretical and experimental explanations of the emission property of a single NV center, is expected to help the utilization of the NV center for quantum information science, quantum communication, and quantum bioimaging.
Currently, the primary applications of fluorescent nanodiamonds (FNDs) are in the area of biosensing, by using photoluminescence or spin properties of colour centres, mainly represented by the Nitrogen Vacancy (NV) point defect. The sensitivity of NV-FNDs to external fields is, however, limited by crystallographic defects, which influence their key quantum state characteristics - the spin longitudinal (\textit{T1_11​}) and spin transversal (\textit{T2_22​}) relaxation and coherence times, respectively. We report on utilising an advanced FND growth technique consisting of heterogeneous nucleation on pre-engineered sites to create FNDs averaging around 60 nm in size, with mean longitudinal coherence times of 800 μμμs and a maximum over 1.8 ms, close to bulk theoretical values. This is a major, nearly ten-fold improvement over commercially available nanodiamonds for the same size range of 50 to 150 nm. Heavy-N doped nanodiamond shells, important for sensing events in nm proximity to the diamond surface, are fabricated and discussed in terms of re-nucleation and twinning on \{111\} crystal facets. We also discuss scalability issues in order to enable the production of FND volumes matching the needs of sensing applications.
The nitrogen vacancy (NV) center in diamond is the most widely studied color center in diamond for its wide range of applications in both physics and biology. The negatively charged state ${\mathrm{NV}}^{\ensuremath{-}}$ is often favored for its better spin-optical properties, whereas the presence of the neutral charge state NV0{\mathrm{NV}}^{0}NV0 is often minimized or neglected by using a single optimized excitation wavelength. In many cases, the use of additional laser wavelengths has an important impact on the NV optical properties and can lead to a dramatically quenched fluorescence. Through measurements of the photophysics of the NV center we show in this work that this quenching mechanism is mediated by charge state interconversion providing additional channels for nonradiative decay. Our results show that this mechanism is also sensitive to the spin state of the ${\mathrm{NV}}^{\ensuremath{-}}$. A better understanding of this physical mechanism will help mitigate the spin and charge state depolarization effects that are detrimental for quantum technology applications.