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

arXiv:2603.28017

Self-Limiting Mechanism of Anti-Stokes Optical Cooling in Diamond NV Centers

Haruki Manaka, Yasuhiro Yamada

Published Mar 30, 2026• 0 citations
arXivHTMLPDF

Abstract

Anti-Stokes optical cooling in diamond nitrogen-vacancy (NV) centers is experimentally and numerically investigated. Photoluminescence-excitation spectroscopy reveals pronounced phonon-assisted anti-Stokes emission under excitation below the zero-phonon line (ZPL). However, the below-ZPL excitation drives photoinduced charge-state conversion between negatively-charged NV- and neutral NV0, thereby suppressing the NV- mediated cooling channel. Time-resolved photoluminescence (PL) measurements reveal an increase in the effective PL lifetime with excitation density, reflecting an increasing NV0 contribution. By fitting nanosecond and millisecond PL dynamics with a minimal rate-equation model, we extract effective optical pumping and charge-conversion rates, which enables us to quantitatively simulate the cooling performance. The simulations predict a self-limiting behavior of anti-Stokes cooling and clarify the excitation conditions under which net cooling can be sustained within this effective model. The estimated cooling power per NV center is comparable, on a microscopic basis, to values discussed for semiconductor quantum dots and rare-earth optical coolers. These results identify charge-state conversion as a key bottleneck for defect-based optical refrigeration.

DOI
10.48550/arxiv.2603.28017

Related papers

Charge-State Dynamics under Phonon-Assisted Excitation in Diamond NV Centers: Implications for Optical Cooling

Haruki Manaka, Yasuhiro Yamada

Anti-Stokes optical cooling in diamond nitrogen-vacancy (NV) centers is investigated using photoluminescence (PL) spectroscopy, time-resolved measurements, and rate-equation modeling. Under excitation below the zero-phonon line, anti-Stokes emission from the negatively charged NV- state appears, but optical excitation also induces charge-state conversion between NV- and neutral NV0. Excitation-dependent PL dynamics reveal a reduction of the NV- population under strong excitation. A minimal rate-equation model constrained by nanosecond and millisecond PL measurements predicts that photoionization suppresses the NV--mediated cooling contribution and leads to self-limiting cooling behavior. The calculations further show that net cooling requires exceptionally high quantum efficiency and does not increase monotonically with excitation density. These results highlight photoinduced charge-state conversion as a key photophysical bottleneck for defect-based anti-Stokes optical cooling.

The Journal of Physical Chemistry Letters•Oct 6, 2026•0 citations

Phonon-Assisted Photoluminescence Up-Conversion of Silicon-Vacancy Centers in Diamond

Yuanfei Gao, Qinghai Tan, Xue‐Lu Liu +7 more

Phonon-assisted anti-Stokes photoluminescence (ASPL) up-conversion lies at the heart of optical refrigeration in solids. The thermal energy contained in the lattice vibrations is taken away by the emitted anti-Stokes photons' ASPL process, resulting in laser cooling of solids. To date, net laser cooling of solids is limited in rare-earth (RE)-doped crystals, glasses, and direct band gap semiconductors. Searching more solid materials with efficient phonon-assisted photoluminescence up-conversion is important to enrich optical refrigeration research. Here, we demonstrate the phonon-assisted PL up-conversion process from the silicon vacancy (SiV) center in diamond for the first time by studying ASPL spectra for the dependence of temperature, laser power, and excitation energy. Although net cooling has not been observed, our results show that net laser cooling might be eventually achieved in diamond by improving the external quantum efficiency to higher than 95%. Our work provides a promising route to investigate the laser cooling effect in diamond.

The Journal of Physical Chemistry Letters•Oct 24, 2018•26 citations

Phonon-assisted charge-cycling of nitrogen-vacancy centres in diamond

M. Olney-Fraser, J. Fuhrmann, S. Dietel +2 more

The nitrogen-vacancy (NV) centre in diamond is a leading platform for room-temperature quantum sensing. Improvements in sensitivity require precise control of the NV charge state. Transitions from the neutral NV$^0$ charge state to the negative NV$^-$ charge state can occur during excitation with photon energies below the ZPL transition of NV$^0$. These sub-resonant charge transitions limit modern initialisation protocols and have not been studied in full detail. In this paper we show that sub-resonant charge cycling arises from phonon-assisted anti-Stokes excitation. We further uncover the phonon states which contribute most strongly to the anti-Stokes transition via the development of novel quantitative models. The models indicate that low energy acoustic phonons strongly contribute to the transition close to the ZPL. At longer wavelengths a 43\,meV mode additionally impacts the charge cycling dynamics.

quant-pharXiv:2605.07891•May 11, 2026•0 citations

Charge State Manipulation of NV Centers in Diamond under Phonon-Assisted Anti-Stokes Excitation of NV0

Yuanfei Gao, Jia‐Min Lai, Yujia Sun +5 more

The manipulation of the charge states of nitrogen-vacancy (NV) centers in diamond is a prerequisite for next-generation quantum sensing, communication, and computing. Here, we use phonon-assisted anti-Stokes excitation to realize the reversible conversion between the NV 0 and NV – states. In this case, we observe two decay processes of NV – centers with lifetimes as long as tens of seconds. By studying the kinetics of spectral structure evolution of NV – states, we find that the spectral structure of the NV – center is modulated by the charge state transition process under anti-Stokes excitation. We propose that the main reason is the local electric field generated by the ionization of the NV –, which changes the radiation environment of the color centers. Our results might provide an alternative method to control the charge states of nitrogen-vacancy centers.

ACS Photonics•Apr 26, 2022•21 citations

Charge-state conversion in nitrogen-vacancy centers mediated by an engineered photonic environment

Sachin Kumar Sharma, Rajesh V. Nair

The nitrogen-vacancy (NV) center in nanodiamonds has emerged as an excellent platform in quantum technologies due to its applications in spin manipulation and nanoscale sensing. However, their use is limited by the unavoidable charge-state conversion under optical pumping. In this study, we investigate the control of charge-state conversion in NV centers using an engineered photonic environment and thus change the available local density of optical states (LDOS). The spectral- and pump-dependent decay rate measurements are performed to study the redistribution of emission rates due to the change in LDOS and their effect on charge-state conversion. We have achieved an 8% enhancement of emission rate at the zero phonon line which is accompanied with a 10% suppression in the phonon sideband emission rate in the low-pump-power regime. In the high-pump-power regime, the charge-state conversion becomes inevitable and leads to the deterioration of LDOS-induced modification in the NV center emission lifetimes. The results are useful for efficient NV center spin readout and charge-state depletion microscopy utilizing reversible charge-state conversion.

Physical Review A•Apr 27, 2020•6 citations

Laser spectroscopic characterization of negatively charged nitrogen-vacancy (NV−) centers in diamond

Shova D. Subedi, Vladimir Fedorov, Jeremy M. Peppers +4 more

We report on the spectroscopic and laser characterization of negatively charged nitrogen-vacancy (NV−) centers in diamond. Spectroscopic properties such as absorption and emission spectra as well as kinetics were studied, and parameters such as cross-sections and lifetimes were estimated. A vibronic band of NV0 with zero phonon line (ZPL) at 575 nm was detected under 532 nm pulsed excitation due to the photoionization of NV−. Transmission of 532 nm pump pulses saturate around ∼10%, which is much smaller than the theoretical level. Δk/k0 kinetics revealed slow recovery of NV− centers after photoionization under 532 nm pumping, which involved different relaxation channels depending on the probe beam wavelengths. Localization of the electrons in the metastable state of NV0 centers resulted in higher saturated transmission of 632 nm pump.

Optical Materials Express•Apr 5, 2019•73 citations
Anti-Stokes optical cooling in diamond nitrogen-vacancy (NV) centers is experimentally and numerically investigated. Photoluminescence-excitation spectroscopy reveals pronounced phonon-assisted anti-Stokes emission under excitation below the zero-phonon line (ZPL). However, the below-ZPL excitation drives photoinduced charge-state conversion between negatively-charged NV- and neutral NV0, thereby suppressing the NV- mediated cooling channel. Time-resolved photoluminescence (PL) measurements reveal an increase in the effective PL lifetime with excitation density, reflecting an increasing NV0 contribution. By fitting nanosecond and millisecond PL dynamics with a minimal rate-equation model, we extract effective optical pumping and charge-conversion rates, which enables us to quantitatively simulate the cooling performance. The simulations predict a self-limiting behavior of anti-Stokes cooling and clarify the excitation conditions under which net cooling can be sustained within this effective model. The estimated cooling power per NV center is comparable, on a microscopic basis, to values discussed for semiconductor quantum dots and rare-earth optical coolers. These results identify charge-state conversion as a key bottleneck for defect-based optical refrigeration.
Anti-Stokes optical cooling in diamond nitrogen-vacancy (NV) centers is investigated using photoluminescence (PL) spectroscopy, time-resolved measurements, and rate-equation modeling. Under excitation below the zero-phonon line, anti-Stokes emission from the negatively charged NV- state appears, but optical excitation also induces charge-state conversion between NV- and neutral NV0. Excitation-dependent PL dynamics reveal a reduction of the NV- population under strong excitation. A minimal rate-equation model constrained by nanosecond and millisecond PL measurements predicts that photoionization suppresses the NV--mediated cooling contribution and leads to self-limiting cooling behavior. The calculations further show that net cooling requires exceptionally high quantum efficiency and does not increase monotonically with excitation density. These results highlight photoinduced charge-state conversion as a key photophysical bottleneck for defect-based anti-Stokes optical cooling.
Phonon-assisted anti-Stokes photoluminescence (ASPL) up-conversion lies at the heart of optical refrigeration in solids. The thermal energy contained in the lattice vibrations is taken away by the emitted anti-Stokes photons' ASPL process, resulting in laser cooling of solids. To date, net laser cooling of solids is limited in rare-earth (RE)-doped crystals, glasses, and direct band gap semiconductors. Searching more solid materials with efficient phonon-assisted photoluminescence up-conversion is important to enrich optical refrigeration research. Here, we demonstrate the phonon-assisted PL up-conversion process from the silicon vacancy (SiV) center in diamond for the first time by studying ASPL spectra for the dependence of temperature, laser power, and excitation energy. Although net cooling has not been observed, our results show that net laser cooling might be eventually achieved in diamond by improving the external quantum efficiency to higher than 95%. Our work provides a promising route to investigate the laser cooling effect in diamond.
The nitrogen-vacancy (NV) centre in diamond is a leading platform for room-temperature quantum sensing. Improvements in sensitivity require precise control of the NV charge state. Transitions from the neutral NV0^00 charge state to the negative NV−^-− charge state can occur during excitation with photon energies below the ZPL transition of NV0^00. These sub-resonant charge transitions limit modern initialisation protocols and have not been studied in full detail. In this paper we show that sub-resonant charge cycling arises from phonon-assisted anti-Stokes excitation. We further uncover the phonon states which contribute most strongly to the anti-Stokes transition via the development of novel quantitative models. The models indicate that low energy acoustic phonons strongly contribute to the transition close to the ZPL. At longer wavelengths a 43\,meV mode additionally impacts the charge cycling dynamics.
The manipulation of the charge states of nitrogen-vacancy (NV) centers in diamond is a prerequisite for next-generation quantum sensing, communication, and computing. Here, we use phonon-assisted anti-Stokes excitation to realize the reversible conversion between the NV 0 and NV – states. In this case, we observe two decay processes of NV – centers with lifetimes as long as tens of seconds. By studying the kinetics of spectral structure evolution of NV – states, we find that the spectral structure of the NV – center is modulated by the charge state transition process under anti-Stokes excitation. We propose that the main reason is the local electric field generated by the ionization of the NV –, which changes the radiation environment of the color centers. Our results might provide an alternative method to control the charge states of nitrogen-vacancy centers.
The nitrogen-vacancy (NV) center in nanodiamonds has emerged as an excellent platform in quantum technologies due to its applications in spin manipulation and nanoscale sensing. However, their use is limited by the unavoidable charge-state conversion under optical pumping. In this study, we investigate the control of charge-state conversion in NV centers using an engineered photonic environment and thus change the available local density of optical states (LDOS). The spectral- and pump-dependent decay rate measurements are performed to study the redistribution of emission rates due to the change in LDOS and their effect on charge-state conversion. We have achieved an 8% enhancement of emission rate at the zero phonon line which is accompanied with a 10% suppression in the phonon sideband emission rate in the low-pump-power regime. In the high-pump-power regime, the charge-state conversion becomes inevitable and leads to the deterioration of LDOS-induced modification in the NV center emission lifetimes. The results are useful for efficient NV center spin readout and charge-state depletion microscopy utilizing reversible charge-state conversion.
We report on the spectroscopic and laser characterization of negatively charged nitrogen-vacancy (NV−) centers in diamond. Spectroscopic properties such as absorption and emission spectra as well as kinetics were studied, and parameters such as cross-sections and lifetimes were estimated. A vibronic band of NV0 with zero phonon line (ZPL) at 575 nm was detected under 532 nm pulsed excitation due to the photoionization of NV−. Transmission of 532 nm pump pulses saturate around ∼10%, which is much smaller than the theoretical level. Δk/k0 kinetics revealed slow recovery of NV− centers after photoionization under 532 nm pumping, which involved different relaxation channels depending on the probe beam wavelengths. Localization of the electrons in the metastable state of NV0 centers resulted in higher saturated transmission of 632 nm pump.