A Four-Channel BiCMOS Transmitter for a Quantum Magnetometer Based on Nitrogen-Vacancy Centers in Diamond
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2024-01-19 |
| Journal | IEEE Journal of Solid-State Circuits |
| Authors | Hadi Lotfi, Michal Kern, Qing Yang, Thomas Unden, Nico Striegler |
| Institutions | University of Stuttgart, Center for Integrated Quantum Science and Technology |
| Citations | 7 |
Abstract
Section titled “Abstract”Quantum sensors based on solid-state defects, such as the nitrogen-vacancy (NV) center in diamond, offer very good room-temperature sensitivity, long-term stability, and the potential for calibration-free measurements. However, most quantum sensors still suffer from a bulky size and weight, low energy efficiency, and high costs, prohibiting their widespread use. Here, we present custom-designed chip-integrated microwave (MW) electronics for a miniaturized, low-cost, and highly scalable quantum magnetometer based on NV centers in diamond. The presented electronics include a quadrature phase-locked loop (QPLL) chip to generate the required local oscillator signal at around 7 GHz with a wide tuning range of 22% and a low phase noise (PN) of <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$-$</tex-math> </inline-formula> 122 dBc/Hz at 1-MHz offset from a 7-GHz carrier for broadband low-noise magnetometry. In addition, the magnetometer electronics comprise a 4-channel transmitter chip, which can provide currents up to 412 mA <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$\text{pp}$</tex-math> </inline-formula> into a custom-designed inductor over a wide frequency range from 6.4 to 8 GHz. In combination with a custom-designed coil, manufactured on a glass substrate for optical transparency, which features a large active area of ( <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$\pi\ttimes 180 \ttimes 180~\mu \text{m}^2$</tex-math> </inline-formula> ), this current is sufficient to produce strong MW magnetic fields up to <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$B\text{1} = (1/2) \cdot B_\text{ac} = 170~{\mu \mathrm{T}}$</tex-math> </inline-formula> , enabling pulsed optically detected magnetic resonance (ODMR) experiments. In proof-of-concept ODMR experiments, the presented chip-based spin control system produces fast Rabi oscillations of 5.49 MHz. The measured dc and ac magnetic field limits of detection (LOD) of the presented magnetometer are 32 nT/Hz <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$^\text{1/2}$</tex-math> </inline-formula> and 300 pT/Hz <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$^\text{1/2}$</tex-math> </inline-formula> , respectively.