Spectroscopy of condensed matter

Fluorescent diamond microcrystals with NV$^-$ centers for applications in photonics and sensors: identification and photophysical signatures

V. Yu. Osipov^a, F. M. Shakhov^a, K. V. Bogdanov^b, K. Takai^c, A. V. Baranov<sup>b

a</sup> Ioffe Institute, St. Petersburg, 194021 St. Petersburg, Russia
^b ITMO University, 197101 St. Petersburg, Russia
^c Department of Chemical Science and Technology, Hosei University, Koganei, 184-8584 Tokyo, Japan

Abstract: Synthetic microcrystalline Ib HPHT diamonds synthesized using a nickel-containing catalyst and containing fluorescent negatively charged nitrogen-vacancy (NV$^-$) centers, specially introduced by irradiation with high-energy electrons, were studied. A set of identification signatures corresponding to diamond microcrystals with high optical brightness and a concentration of NV$^-$ centers of about 4.5 ppm is shown. Electron paramagnetic resonance signals for nitrogen impurity atoms in the neutral state and nickel in the -1 charge state depend on temperature according to Curie’s law, while the signal $g$ = 4.295 (W15), associated with $\Delta m_s$ = 2 transitions in the NV$^-$ center, demonstrates a different type temperature behavior. Illumination of microcrystals with light in the spectral range of 1.38–2.95 eV at $T$ = 100 K entails optical spin polarization for the $m_s$ = 0 level of the ground unexcited state of $^3$A$_2$ NV$^-$ centers. Synthesized diamond microcrystals can be used in photonics devices.

Keywords: diamond microcrystals, nitrogen-vacancy centers, paramagnetic centers, luminescence, electron paramagnetic resonance.

Received: 21.11.2023
Revised: 21.11.2023
Accepted: 30.11.2023

DOI: 10.61011/OS.2023.12.57401.5776-23

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