Optimization and characterization of laser excitation for quantum sensing with single nitrogen-vacancy centres

Abstract:

In this work we present a comprehensive method of characterization and optimization of laser

irradiation within a confocal microscope tailored to quantum sensing experiments using nitrogenvacancy

(NV) centres. While confocal microscopy is well-suited for such experiments, precise control

and understanding of several optical parameters are essential for reliable single-emitter studies. We

investigate the laser beam intensity profile, single-photon emission statistics, fluorescence response

under varying polarization and saturation conditions, spectral characteristics, and the temporal profiles

of readout and reinitialization pulses. The beam quality is assessed using the beam propagation

factor M2, determined via the razorblade technique. Optical fluorescence spectrum is recorded to

confirm NV centre emission. To confirm single-emitter operation, we measure second-order autocorrelation

function g(2)(τ ). Saturation behaviour is analysed by varying laser power and recording the

corresponding fluorescence, while polarization dependence is studied using a half-wave (λ/2) plate.

Temporal laser pulse profile is examined by modulating the power of an acousto-optic modulator.

After optimizing all relevant parameters, we demonstrate the microscope’s capabilities in driving

spin transitions of a single NV centre. This work establishes a straightforward and effective protocol

for laser excitation optimization, enhancing the performance and reliability of NV-based quantum

sensors.

Autorzy / Authors:

A. Martınez-Mendez, J. Moreno-Meseguer, M. Mrozek A. Wojciechowski, R. G. Brower, P. Balasubramanian, F. Jelezko and J. Prior

Czasopismo:

J. Appl. Phys., 139, 051101

Rok:

2026

Tematyka badań:

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