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

OSA Continuum

Multi-focal laser fabrication of nitrogen vacancy centres in a bulk diamond

Martina Barbiero, Stefania Castelletto, Miṅ Gu

Published Sep 16, 2020• 5 citations
Publisher

Abstract

We demonstrate the multi-focal fabrication of single N V − centres at different depths in a bulk diamond. After performing an annealing process, the optically detected magnetic resonance (ODMR) signal is measured to confirm the generation of N V − centres. These emitters are photo-stable and are imaged by using three different excitations wavelengths at different depths close to the bulk diamond surface. Using two-photon microscopy, the N V − centres are imaged with a resolution down to 0.36 µm to study the effect of the exposure time of the multi-focal laser writing on the spatial resolution of each fabrication. The Hanbury Brown and Twiss (HBT) test is performed with two-photon excitation to study the number of N V − centres at the location of each multi-focal fabrication. We demonstrate the formation of single N V − centres placed between 100 nm and 3 µm below the diamond surface. The ability to control the placement of single N V − centres with depth is of paramount importance for applications in quantum information, single spin magnetometry, and optical data storage.

DOI
10.1364/osac.401871

Related papers

Optical detection of magnetic resonance in nitrogen vacancy centre ensembles in bulk diamond using an off-resonant probe laser beam

C. D. Macrae, Elisabeth Fraczek, Mark E. Newton +11 more

Nitrogen vacancy (NV) centres are a type of defect in diamond that exhibit a number of interesting properties. NV centres can be optically excited around 450-650 nm and emit fluorescence at around 550-800 nm [1]. The optical excitation also spin polarises the negatively charged NV centres, permitting optical detection of magnetic resonance [2]. This allows nanotesla scale sensitive magnetometry to be performed with nanometre scale spatial resolution [3].To date, a direct measurement of stimulated emission from ensembles of NV centres in diamond has yet to be demonstrated experimentally. Despite this, stimulated emission depletion microscopy has been utilised in superresolution imaging that relies on the stimulated emission of single NV centres to quench fluorescence [4]. Recently, there has also been similar indirect experimental evidence of stimulated emission in NV ensembles [5]. We thus aimed to show both optical gain of a probe beam in a pumped NV-rich diamond sample and a modulation of this gain via microwave excitation of its ground level spin transitions. The experimental set-up consisted of a pump (532 nm) and probe (723-950 nm) laser beam combined with a dichroic mirror and focused into a bulk diamond specimen to a spot-size of around 90 microns. Pump excitation powers of up to 3 W and probe powers up to 0.5 W were used. The beams were then collimated and separated with a prism and the probe power measured with a photodiode. The diamond specimen was placed on an antenna to allow simultaneous excitation with microwaves. A double modulation scheme was employed to measure either the change in probe power due to the pump laser or the microwave excitation during any one experiment.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2017•0 citations

Optically detected magnetic resonance of nitrogen-vacancy centers in diamond using two-photon excitation

Lam T. Nguyen, Khanh Kieu

We demonstrate the use of two-photon excitation for observing the ground state optically detected magnetic resonance (ODMR) of nitrogen-vacancy centers in diamonds at room temperature. An ultrafast femtosecond laser at 1040 nm was used for excitation, while fluorescence signal read out was achieved through a combination of a PMT and a lock-in amplifier. The imaging capability of two-photon excitation fluorescence (2PEF) was utilized to map the distribution of NV centers in a bulk diamond and micro-sized diamonds. For the first time, ODMR traces of the nitrogen-vacancy center are observed with two-photon excitation, providing a promising tool for fast 3D quantum sensing and imaging.

quant-pharXiv:2604.15755•Apr 20, 2026•0 citations

Optically detected magnetic resonance of nitrogen-vacancy centers in diamond using two-photon excitation

Lam T. Nguyen, Khanh Quoc Kieu

We demonstrate the use of two-photon excitation for observing the ground-state optically detected magnetic resonance (ODMR) of nitrogen-vacancy centers in diamonds at room temperature. An ultrafast femtosecond laser at 1040 nm was used for excitation, while fluorescence signal readout was achieved through a combination of a PMT and a lock-in amplifier. The imaging capability of two-photon excitation fluorescence (2PEF) was utilized to map the relative distribution of NV centers in a bulk diamond and micro-sized diamonds. For the first time, to the best of our knowledge, ODMR traces of the nitrogen-vacancy center are observed with two-photon excitation, providing a promising tool for fast 3D quantum sensing and imaging.

Optics Letters•Jun 22, 2026•0 citations

Nitrogen-vacancy centre formation via local femto-second laser annealing of diamond

Davin Yue Ming Peng, Alexander J. Healey, Rebecca Griffin +7 more

Emerging quantum technologies based on the nitrogen-vacancy (NV) centre in diamond require carefully engineered material with controlled defect density, optimised NV formation processes, and minimal crystal strain. The choice of NV generation technique plays a crucial role in determining the quality and performance of these centres. In this work, we investigate NV centre formation in nitrogen-doped diamond using femtosecond (fs) laser processing. We systematically examine the effect of laser pulse energy on NV production and quality using photoluminescence and optically detected magnetic resonance measurements. We also probe the role of pre-existing lattice defects formed by electron irradiation and consider defect evolution over extended dwell times. Finally, we are able to identify a regime where the main action of the fs-laser is to diffuse rather than create vacancies. This local annealing capability expands the toolkit for tailored NV production and presents opportunities for fine tuning defect populations.

arXiv:2507.18027•Carbon•Sep 30, 2025•4 citations

Perfectly aligned shallow ensemble nitrogen-vacancy centers in (111) diamond

Hitoshi Ishiwata, Makoto Nakajima, Kosuke Tahara +3 more

We report the formation of perfectly aligned, high-density, shallow nitrogen vacancy (NV) centers on the (111) surface of a diamond. The study involved step-flow growth with a high flux of nitrogen during chemical vapor deposition (CVD) growth, which resulted in the formation of a highly concentrated (>1019 cm−3) nitrogen layer approximately 10 nm away from the substrate surface. Photon counts obtained from the NV centers indicated the presence of 6.1 × 1015–3.1 × 1016 cm−3 NV centers, which suggested the formation of an ensemble of NV centers. The optically detected magnetic resonance (ODMR) spectrum confirmed perfect alignment (more than 99%) for all the samples fabricated by step-flow growth via CVD. Perfectly aligned shallow ensemble NV centers indicated a high Rabi contrast of approximately 30% which is comparable to the values reported for a single NV center. Nanoscale nuclear magnetic resonance demonstrated surface-sensitive nuclear spin detection and provided a confirmation of the NV centers' depth. Single NV center approximation indicated that the depth of the NV centers was approximately 9–10.7 nm from the surface with error of less than ±0.8 nm. Thus, a route for material control of shallow NV centers has been developed by step-flow growth using a CVD system. Our finding pioneers on the atomic level control of NV center alignment for large area quantum magnetometry.

arXiv:1704.03642•Applied Physics Letters•Jul 24, 2017•60 citations

Nitrogen vacancy centres in diamond for laser threshold magnetometry

Zahraa Al-Baiaty, Felix A. Hahl, Sarath Raman Nair +6 more

High precision magnetometry is important for a range of applications from the monitoring of biologically generated magnetic fields (e.g. magnetoencephalography and magnetocardiography), to navigation in GPS denied environments, to the detection of gravitational waves. Diamond containing the negatively-charged nitrogen vacancy colour centre (NV-) has emerged as a powerful room-temperature sensing solution. Here we explore NV- centres as a laser medium for a new form of magnetometry: laser threshold magnetometry (LTM). LTM works by placing NV- inside an optical cavity and uses the coherent laser output as a potentially more sensitive readout channel than is possible using conventional (incoherent) optically detected magnetic resonance. Here we show progress towards LTM with diamond. We show twolaser excitation and stimulated emission in free space, and report progress towards diamond-cavity experiments. Our studies highlight the need for different NV- optimisation for laser applications, rather than those conventionally used for quantum information applications

Biophotonics Australasia•Dec 30, 2019•0 citations
We demonstrate the multi-focal fabrication of single N V − centres at different depths in a bulk diamond. After performing an annealing process, the optically detected magnetic resonance (ODMR) signal is measured to confirm the generation of N V − centres. These emitters are photo-stable and are imaged by using three different excitations wavelengths at different depths close to the bulk diamond surface. Using two-photon microscopy, the N V − centres are imaged with a resolution down to 0.36 µm to study the effect of the exposure time of the multi-focal laser writing on the spatial resolution of each fabrication. The Hanbury Brown and Twiss (HBT) test is performed with two-photon excitation to study the number of N V − centres at the location of each multi-focal fabrication. We demonstrate the formation of single N V − centres placed between 100 nm and 3 µm below the diamond surface. The ability to control the placement of single N V − centres with depth is of paramount importance for applications in quantum information, single spin magnetometry, and optical data storage.
Nitrogen vacancy (NV) centres are a type of defect in diamond that exhibit a number of interesting properties. NV centres can be optically excited around 450-650 nm and emit fluorescence at around 550-800 nm [1]. The optical excitation also spin polarises the negatively charged NV centres, permitting optical detection of magnetic resonance [2]. This allows nanotesla scale sensitive magnetometry to be performed with nanometre scale spatial resolution [3].To date, a direct measurement of stimulated emission from ensembles of NV centres in diamond has yet to be demonstrated experimentally. Despite this, stimulated emission depletion microscopy has been utilised in superresolution imaging that relies on the stimulated emission of single NV centres to quench fluorescence [4]. Recently, there has also been similar indirect experimental evidence of stimulated emission in NV ensembles [5]. We thus aimed to show both optical gain of a probe beam in a pumped NV-rich diamond sample and a modulation of this gain via microwave excitation of its ground level spin transitions. The experimental set-up consisted of a pump (532 nm) and probe (723-950 nm) laser beam combined with a dichroic mirror and focused into a bulk diamond specimen to a spot-size of around 90 microns. Pump excitation powers of up to 3 W and probe powers up to 0.5 W were used. The beams were then collimated and separated with a prism and the probe power measured with a photodiode. The diamond specimen was placed on an antenna to allow simultaneous excitation with microwaves. A double modulation scheme was employed to measure either the change in probe power due to the pump laser or the microwave excitation during any one experiment.
We demonstrate the use of two-photon excitation for observing the ground state optically detected magnetic resonance (ODMR) of nitrogen-vacancy centers in diamonds at room temperature. An ultrafast femtosecond laser at 1040 nm was used for excitation, while fluorescence signal read out was achieved through a combination of a PMT and a lock-in amplifier. The imaging capability of two-photon excitation fluorescence (2PEF) was utilized to map the distribution of NV centers in a bulk diamond and micro-sized diamonds. For the first time, ODMR traces of the nitrogen-vacancy center are observed with two-photon excitation, providing a promising tool for fast 3D quantum sensing and imaging.
We demonstrate the use of two-photon excitation for observing the ground-state optically detected magnetic resonance (ODMR) of nitrogen-vacancy centers in diamonds at room temperature. An ultrafast femtosecond laser at 1040 nm was used for excitation, while fluorescence signal readout was achieved through a combination of a PMT and a lock-in amplifier. The imaging capability of two-photon excitation fluorescence (2PEF) was utilized to map the relative distribution of NV centers in a bulk diamond and micro-sized diamonds. For the first time, to the best of our knowledge, ODMR traces of the nitrogen-vacancy center are observed with two-photon excitation, providing a promising tool for fast 3D quantum sensing and imaging.
Emerging quantum technologies based on the nitrogen-vacancy (NV) centre in diamond require carefully engineered material with controlled defect density, optimised NV formation processes, and minimal crystal strain. The choice of NV generation technique plays a crucial role in determining the quality and performance of these centres. In this work, we investigate NV centre formation in nitrogen-doped diamond using femtosecond (fs) laser processing. We systematically examine the effect of laser pulse energy on NV production and quality using photoluminescence and optically detected magnetic resonance measurements. We also probe the role of pre-existing lattice defects formed by electron irradiation and consider defect evolution over extended dwell times. Finally, we are able to identify a regime where the main action of the fs-laser is to diffuse rather than create vacancies. This local annealing capability expands the toolkit for tailored NV production and presents opportunities for fine tuning defect populations.
We report the formation of perfectly aligned, high-density, shallow nitrogen vacancy (NV) centers on the (111) surface of a diamond. The study involved step-flow growth with a high flux of nitrogen during chemical vapor deposition (CVD) growth, which resulted in the formation of a highly concentrated (>1019 cm−3) nitrogen layer approximately 10 nm away from the substrate surface. Photon counts obtained from the NV centers indicated the presence of 6.1 × 1015–3.1 × 1016 cm−3 NV centers, which suggested the formation of an ensemble of NV centers. The optically detected magnetic resonance (ODMR) spectrum confirmed perfect alignment (more than 99%) for all the samples fabricated by step-flow growth via CVD. Perfectly aligned shallow ensemble NV centers indicated a high Rabi contrast of approximately 30% which is comparable to the values reported for a single NV center. Nanoscale nuclear magnetic resonance demonstrated surface-sensitive nuclear spin detection and provided a confirmation of the NV centers' depth. Single NV center approximation indicated that the depth of the NV centers was approximately 9–10.7 nm from the surface with error of less than ±0.8 nm. Thus, a route for material control of shallow NV centers has been developed by step-flow growth using a CVD system. Our finding pioneers on the atomic level control of NV center alignment for large area quantum magnetometry.
High precision magnetometry is important for a range of applications from the monitoring of biologically generated magnetic fields (e.g. magnetoencephalography and magnetocardiography), to navigation in GPS denied environments, to the detection of gravitational waves. Diamond containing the negatively-charged nitrogen vacancy colour centre (NV-) has emerged as a powerful room-temperature sensing solution. Here we explore NV- centres as a laser medium for a new form of magnetometry: laser threshold magnetometry (LTM). LTM works by placing NV- inside an optical cavity and uses the coherent laser output as a potentially more sensitive readout channel than is possible using conventional (incoherent) optically detected magnetic resonance. Here we show progress towards LTM with diamond. We show twolaser excitation and stimulated emission in free space, and report progress towards diamond-cavity experiments. Our studies highlight the need for different NV- optimisation for laser applications, rather than those conventionally used for quantum information applications