Bonn 2025 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 30: Quantum Sensing I (joint session Q/QI)

Q 30.6: Vortrag

Mittwoch, 12. März 2025, 12:15–12:30, HS V

A Miniaturized Fiber-Based Magnetic Field Sensor Based on Nitrogen-Vacancy Centers — •Stefan Johansson, Dennis Lönard, Isabel Cardoso Barbosa, Jonas Gutsche, and Artur Widera — Physics Department and State Research Center OPTIMAS, RPTU Kaiserslautern-Landau, 67663 Kaiserslautern, Germany

Sensing based on quantum effects is believed to be one of the technologies of the near future. Among other quantum magnetic field sensors, such as optically pumped magnetometers and superconducting interference devices, the nitrogen-vacancy (NV) center in diamond is a prime candidate for measuring magnetic fields. It provides a solid crystalline platform operating under ambient conditions without extensive cooling or encapsulation. This chemically and physically robust diamond platform allows measurements in direct contact with a sample, making it highly sensitive to an emitted field, e.g., from muscle signals or magnetic surfaces. While many fiber-based sensors have been published, only a few are portable or provide the capability to measure vectorial magnetic fields using optically detected magnetic resonance measurements. Here, we present our flexible, portable, yet robust fiber-based sensor. The design allows the use of lithographic processes such as direct laser writing of elementary silver and polymer structures on the optical fiber tip. The silver structure allows excitations using microwaves, while the polymer waveguide structure guides excitation and fluorescence light and is used to fixate a 15 μm-sized diamond to the tip of the optical fiber. We verify the capabilities of our sensor in vectorial measurements of a magnetic coil system.

Keywords: nitrogen-vacancy center; NV center; DLW; direct laser writing; magnetometer