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arXiv:2602.07536

Characterization of Autofluorescence in Optical Fibers for NV-based Sensing Applications

Stefan Johansson, Alexander Bukschat, Dennis Lönard, Alena Erlenbach, Jonas Gutsche, Artur Widera

quant-phphysics.opticsSubmitted Feb 7, 2026• Announced Feb 10, 2026• 0 citations
arXivHTMLPDF

Abstract

Optical fibers are crucial for guiding light in various sensing applications. Especially for quantum sensors such as the nitrogen-vacancy (NV) center in diamond, they enable light control and device miniaturization. However, fluorescence and scattering within the fiber, often referred to as fiber background, autofluorescence, or autoluminescence, can overlap spectrally with the NV centers' fluorescence, degrading the signal-to-noise ratio and thus limiting sensor sensitivity. Here, we investigate the optical spectra of standard optical fibers, considering material dependencies, physical influences, and their fluorescence scaling with excitation power and wavelength. Our results identify spectral components and fiber types with minimal unwanted background signals, guiding the selection of optimal fibers for NV-based quantum sensing.

Comments
15 pages, 7 figures

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Optical fibers are crucial for guiding light in various sensing applications. Especially for quantum sensors such as the nitrogen-vacancy (NV) center in diamond, they enable light control and device miniaturization. However, fluorescence and scattering within the fiber, often referred to as fiber background, autofluorescence, or autoluminescence, can overlap spectrally with the NV centers' fluorescence, degrading the signal-to-noise ratio and thus limiting sensor sensitivity. Here, we investigate the optical spectra of standard optical fibers, considering material dependencies, physical influences, and their fluorescence scaling with excitation power and wavelength. Our results identify spectral components and fiber types with minimal unwanted background signals, guiding the selection of optimal fibers for NV-based quantum sensing.
Diamond containing the nitrogen-vacancy (NV) center is emerging as a significant sensing platform. However, most NV sensors require microscopes to collect the fluorescence signals and therefore are limited to laboratory settings. By embedding micron-scale diamond particles at an annular interface within the cross section of a silicate glass fiber, we demonstrate a robust fiber material capable of sensing magnetic fields. Luminescence spectroscopy and electron spin resonance characterization reveal that the optical properties of NV centers in the diamond microcrystals are well preserved throughout the fiber drawing process. The hybrid fiber presents a low propagation loss of ∼4.0 dB/m in the NV emission spectral window, permitting remote monitoring of the optically detected magnetic resonance signals. We demonstrate NV-spin magnetic resonance readout through 50 cm of fiber. This study paves a way for the scalable fabrication of fiber-based diamond sensors for field-deployable quantum metrology applications.
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Nitrogen-vacancy (NV) centers in single-crystal CVD diamond are promising candidates for quantum sensing due to their remarkable optical and spin properties [1]. These defects exhibit stable photoluminescence (PL), long spin coherence times, and high sensitivity to external fields [2]. In this study, we present a room-temperature PL characterization of NV centers excited with a 532 nm laser. The setup was optimized for high signal-to-noise ratio and spectral resolution. Key parameters analyzed include emission intensity, zero-phonon line (ZPL) at ~637 nm, phonon sidebands, and the charge state distribution between NV⁰ and NV⁻. The NV⁻ state, crucial for spin-based sensing, is evaluated to understand its stability under different nitrogen doping conditions [3]. The relative intensities of NV⁰ and NV⁻ provide insights into nitrogen incorporation and vacancy formation. These results contribute to optimizing synthesis conditions for enhanced NV⁻ concentration, supporting the advancement of diamond-based quantum sensing technologies.
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