Integration of High-Brightness QLED-Excited Diamond NV Magnetic Sensing Probe

This article presents a novel nitrogen-vacancy (NV) center magnetic sensing probe that utilizes quantum dot light-emitting diodes (QLEDs) as the excitation light source for the NV centers. The QLED employed in this magnetic sensing probe offers several advantages, including high brightness, controllable light emission area, and ease of fabrication. Key steps in the preparation of the magnetic sensing probe are outlined, and the performance metrics of the NV center magnetic sensing probe are evaluated. Notably, the peak brightness of the quantum dot light-emitting diode reaches 83200 cd/m2, with an electroluminescence (EL) peak at 532 nm. The probe is capable of measuring magnetic fields in the range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pm 142.9~\mu $ </tex-math></inline-formula>T, exhibiting a photon shot noise of 12 nT <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula> Hz−1/2 and an optimal magnetic noise spectral density of 22.6 nT Hz−1/2, all within a compact volume of only 315 mm3. This enables the device to detect weak magnetic fields across various scenarios. The design of the magnetic sensing probe validates the excitation effectiveness of QLEDs on diamond NV centers, providing a new solution for the future development of planar and integrated magnetometer devices through micro-nanofabrication techniques.