29.2 A Scalable Quantum Magnetometer in 65nm CMOS with Vector-Field Detection Capability

Abstract

Room-temperature control and detection of the nitrogen vacancy (NV) center in diamond’s spin-state has enabled magnetic sensing with high sensitivity and spatial resolution [1], [2]. However, current NV sensing apparatuses use bulky off-the-shelf components, which greatly increase the system’s scale. In [3], a compact platform, which attaches nanodiamond particles to a CMOS sensor, shrinks this spin-based magnetometer to chip scale; however, the optically detected magnetic resonance (ODMR) curve it generates carries large fluctuation leading to inferior sensitivity. In this paper, we present a CMOS-NV quantum sensor with (i) a highly-scalable microwave-delivering structure and (ii) a Talboteffect-based photonic filter with enhanced green-to-red suppression ratio. The former enables coherent driving of an increased number of NV centers, and the latter reduces the shot noise of the photo-detector caused by the input green laser. In addition, the usage of a bulk diamond also enables vector magnetometry, which allows for the tracking of magnetic objects and navigation. The prototype sensor provides a measured vector-field sensitivity of 245nT/Hz $^{1/2}$.