Efficient control and readout of electron spins using custom integrated circuits

Abstract

In recent decades, the precise manipulation and control of electron spin states have become essential in the development of spintronic sensors. This progress is particularly crucial in fields such as electron paramagnetic resonance (EPR) spectroscopy and quantum sensing based on optically detected magnetic resonance (ODMR) techniques. These spintronic techniques, rooted in quantum mechanics, exploit the intrinsic magnetic properties of particles with unpaired electrons to probe their environment, offering excellent room-temperature sensitivity, long-term stability, and potential for calibration-free measurements. In these applications, an external RF/microwave magnetic field can be employed to manipulate the spin states of NV centers in quantum magnetometry or samples with unpaired electrons in EPR spectroscopy. Concurrently, RF integrated circuits (RFICs) have revolutionized a broad range of applications, from wireless communication systems to medical devices and sensing technologies, due to their excellent performance, compactness, efficiency, and cost-effectiveness. Despite these advancements, conventional quantum sensors and EPR spectrometers typically rely on commercial vector signal generators (VSGs) and bulky, rack-based microwave (MW) amplifiers to generate the required microwave magnetic fields for spin manipulation. This traditional approach severely limits the portability, scalability, and affordability of electron spin-based sensors, making them less practical for widespread use. To overcome these limitations, we propose leveraging custom-designed, chip-integrated RF/microwave sources and transceivers. By integrating these components onto a single chip, we can significantly enhance the portability and scalability of quantum sensors and EPR systems. These on-chip solutions can generate the necessary microwave fields via embedded coils in voltage-controlled oscillators (VCOs) or custom-designed transceivers driving on-chip or off-chip resonators. In this study, we propose eight different chip-scale systems realized through the tight integration of electronics, electromagnetics, and qubits/spectroscopy on BiCMOS and GaN technologies. For ODMR-based quantum magnetometry, we present three different TX frontend configurations: a high-performance BiCMOS TX-chip operating in the Sband frequency (zero-field) with a novel custom resonator for large active area NV-based magnetometry, a 4-channel BiCMOS transmitter chip with a quadrature phase-locked loop (QPLL) for wide frequency range C-band applications, and a high-performance GaN technology chip utilizing a novel parallel LC-resonator for efficient on-chip microwave magnetic field generation. Furthermore, we detail the design and fabrication of a novel RF transceiver chip and three high-performance PLL chips using SiGe BiCMOS technology for EPR spectroscopy. These PLL chips incorporate VCOs with varying sensing areas and performance levels to accommodate different EPR experimental requirements. By employing these advanced RFICs, we aim to create more compact, efficient, and scalable solutions for spin-based measurements, paving the way for broader adoption and new applications in both scientific research and industry.