High-Scalability CMOS Quantum Magnetometer With Spin-State Excitation and Detection of Diamond Color Centers
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2020-10-09 |
| Journal | IEEE Journal of Solid-State Circuits |
| Authors | Mohamed I. Ibrahim, Christopher Foy, Dirk Englund, Ruonan Han |
| Institutions | Massachusetts Institute of Technology |
| Citations | 52 |
Abstract
Section titled āAbstractāMagnetometers based on quantum mechanical processes enable high sensitivity and long-term stability without the need for re-calibration, but their integration into fieldable devices remains challenging. This article presents a CMOS quantum vector-field magnetometer that miniaturizes the conventional quantum sensing platforms using nitrogen-vacancy (NV) centers in diamond. By integrating key components for spin control and readout, the chip performs magnetometry through optically detected magnetic resonance (ODMR) through a diamond slab attached to a custom CMOS chip. The ODMR control is highly uniform across the NV centers in the diamond, which is enabled by a CMOS-generated ~2.87 GHz magnetic field with <; 5% inhomogeneity across a large-area current-driven wire array. The magnetometer chip is 1.5 mm <sup xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā xmlns:xlink=āhttp://www.w3.org/1999/xlinkā>2</sup> in size, prototyped in 65-nm bulk CMOS technology, and attached to a 300 Ć 80 Ī¼ m <sup xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā xmlns:xlink=āhttp://www.w3.org/1999/xlinkā>2</sup> diamond slab. NV fluorescence is measured by CMOS-integrated photodetectors. This ON-chip measurement is enabled by efficient rejection of the green pump light from the red fluorescence through a CMOS-integrated spectral filter based on a combination of spectrally dependent plasmonic losses and diffractive filtering in the CMOS back-end-of-line (BEOL). This filter achieves a measured ~25 dB of green light rejection. We measure a sensitivity of 245 nT/Hz <sup xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā xmlns:xlink=āhttp://www.w3.org/1999/xlinkā>1/2</sup> , marking a 130 Ć improvement over a previous CMOS-NV sensor prototype, largely thanks to the better spectral filtering and homogeneous microwave generation over larger area.
Tech Support
Section titled āTech SupportāOriginal Source
Section titled āOriginal SourceāReferences
Section titled āReferencesā- 2019 - Sensitivity optimization for NV-diamond magnetometry
- 2019 - Cross-sensor feedback stabilization of an emulated quantum spin gyroscope