Optimised frequency modulation for continuous-wave optical magnetic resonance sensing using nitrogen-vacancy ensembles

Haitham El-Ella, Sepehr Ahmadi, Adam Wojciechowski, Alexander Huck, Ulrik Lund Andersen

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Abstract

Magnetometers based on ensembles of nitrogen-vacancy centres are a promising platform for continuously sensing static and low-frequency magnetic fields. Their combination with phase-sensitive (lock-in) detection creates a highly versatile sensor with a sensitivity that is proportional to the derivative of the optical magnetic resonance lock-in spectrum, which is in turn dependant on the lock-in modulation parameters. Here we study the dependence of the lock-in spectral slope on the modulation of the spin-driving microwave field. Given the presence of the intrinsic nitrogen hyperfine spin transitions, we experimentally show that when the ratio between the hyperfine linewidth and their separation is ≥ 1=4, square-wave based frequency modulation generates the steepest slope at modulation depths exceeding the separation of the hyperfine lines, compared to sine-wave based modulation. We formulate a model for calculating lock-in spectra which shows excellent agreement with our experiments, and which shows that an optimum slope is achieved when the linewidth/separation ratio is ≥ 1=4 and the modulation depth is less then the resonance linewidth, irrespective of the modulation function used.
Original languageEnglish
JournalOpt. Express
Volume25
Issue number13
Pages (from-to)14809-14821
Number of pages13
ISSN1094-4087
DOIs
Publication statusPublished - 2017

Cite this

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title = "Optimised frequency modulation for continuous-wave optical magnetic resonance sensing using nitrogen-vacancy ensembles",
abstract = "Magnetometers based on ensembles of nitrogen-vacancy centres are a promising platform for continuously sensing static and low-frequency magnetic fields. Their combination with phase-sensitive (lock-in) detection creates a highly versatile sensor with a sensitivity that is proportional to the derivative of the optical magnetic resonance lock-in spectrum, which is in turn dependant on the lock-in modulation parameters. Here we study the dependence of the lock-in spectral slope on the modulation of the spin-driving microwave field. Given the presence of the intrinsic nitrogen hyperfine spin transitions, we experimentally show that when the ratio between the hyperfine linewidth and their separation is ≥ 1=4, square-wave based frequency modulation generates the steepest slope at modulation depths exceeding the separation of the hyperfine lines, compared to sine-wave based modulation. We formulate a model for calculating lock-in spectra which shows excellent agreement with our experiments, and which shows that an optimum slope is achieved when the linewidth/separation ratio is ≥ 1=4 and the modulation depth is less then the resonance linewidth, irrespective of the modulation function used.",
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volume = "25",
pages = "14809--14821",
journal = "Optics Express",
issn = "1094-4087",
publisher = "The Optical Society",
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Optimised frequency modulation for continuous-wave optical magnetic resonance sensing using nitrogen-vacancy ensembles. / El-Ella, Haitham; Ahmadi, Sepehr; Wojciechowski, Adam; Huck, Alexander; Andersen, Ulrik Lund.

In: Opt. Express, Vol. 25, No. 13, 2017, p. 14809-14821.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Optimised frequency modulation for continuous-wave optical magnetic resonance sensing using nitrogen-vacancy ensembles

AU - El-Ella, Haitham

AU - Ahmadi, Sepehr

AU - Wojciechowski, Adam

AU - Huck, Alexander

AU - Andersen, Ulrik Lund

PY - 2017

Y1 - 2017

N2 - Magnetometers based on ensembles of nitrogen-vacancy centres are a promising platform for continuously sensing static and low-frequency magnetic fields. Their combination with phase-sensitive (lock-in) detection creates a highly versatile sensor with a sensitivity that is proportional to the derivative of the optical magnetic resonance lock-in spectrum, which is in turn dependant on the lock-in modulation parameters. Here we study the dependence of the lock-in spectral slope on the modulation of the spin-driving microwave field. Given the presence of the intrinsic nitrogen hyperfine spin transitions, we experimentally show that when the ratio between the hyperfine linewidth and their separation is ≥ 1=4, square-wave based frequency modulation generates the steepest slope at modulation depths exceeding the separation of the hyperfine lines, compared to sine-wave based modulation. We formulate a model for calculating lock-in spectra which shows excellent agreement with our experiments, and which shows that an optimum slope is achieved when the linewidth/separation ratio is ≥ 1=4 and the modulation depth is less then the resonance linewidth, irrespective of the modulation function used.

AB - Magnetometers based on ensembles of nitrogen-vacancy centres are a promising platform for continuously sensing static and low-frequency magnetic fields. Their combination with phase-sensitive (lock-in) detection creates a highly versatile sensor with a sensitivity that is proportional to the derivative of the optical magnetic resonance lock-in spectrum, which is in turn dependant on the lock-in modulation parameters. Here we study the dependence of the lock-in spectral slope on the modulation of the spin-driving microwave field. Given the presence of the intrinsic nitrogen hyperfine spin transitions, we experimentally show that when the ratio between the hyperfine linewidth and their separation is ≥ 1=4, square-wave based frequency modulation generates the steepest slope at modulation depths exceeding the separation of the hyperfine lines, compared to sine-wave based modulation. We formulate a model for calculating lock-in spectra which shows excellent agreement with our experiments, and which shows that an optimum slope is achieved when the linewidth/separation ratio is ≥ 1=4 and the modulation depth is less then the resonance linewidth, irrespective of the modulation function used.

U2 - 10.1364/OE.25.014809

DO - 10.1364/OE.25.014809

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SP - 14809

EP - 14821

JO - Optics Express

JF - Optics Express

SN - 1094-4087

IS - 13

ER -