Integrated and Endoscopic NV-Based Quantum Magnetometer

Nitrogen-vacancy (NV) centers in diamond show disruptive potential in quantum sensing, enabling groundbreaking applications in nanoscale microscopy [1] and single-cell imaging [2]. They also promise insight into processes in complex electrochemical systems such as batteries [3]. However, most successes in these applications remain bound to laboratory conditions.

We present a novel architecture for an endoscopic and fully fiber-coupled quantum magnetometer. Our sensor features a 5 mm diameter head with a micro-lens optical front-end for efficient optical excitation and fluorescence collection. An FPGA integrates the control and readout functionalities, including microwave synthesis and lock-in demodulation. This highly integrated platform achieves a magnetic field sensitivity of 150 pT/√Hz, presenting a performance record for endoscopic CW-ODMR based NV-based sensors. We verify the sensor's practical utility by performing 2D magnetic field scans of a commercial battery, demonstrating its capability in a real application scenario. This work marks a significant advance in the transition of endoscopic quantum sensors from the lab to the field.

References:

[1] R. P. Friedrich et al., Int J Nanomedicine 17, 2139-2163 (2022)

[2] A. Pointner et al., J. Phys. Chem. Lett. 16, 7584-7590 (2025)

[3] S. Pollok et al., Nat. Com. 16, 8303 (2025)