The field of nanoscale magnetic resonance imaging (NanoMRI) was started 30 years ago. It was motivated by the desire to image single molecules and molecular assemblies, such as proteins and virus particles, with near-atomic spatial resolution and on a length scale of 100 nm. Over the years, the NanoMRI field has also expanded to include the goal of useful high-resolution nuclear magnetic resonance (NMR) spectroscopy of molecules under ambient conditions, including samples up to the micron-scale. The realization of these goals requires the development of spin detection techniques that are many orders of magnitude more sensitive than conventional NMR and MRI, capable of detecting and controlling nanoscale ensembles of spins. Over the years, a number of different technical approaches to NanoMRI have emerged, each possessing a distinct set of capabilities for basic and applied areas of science. The goal of this roadmap article is to report the current state of the art in NanoMRI technologies, outline the areas where they are poised to have impact, identify the challenges that lie ahead, and propose methods to meet these challenges. This roadmap also shows how developments in NanoMRI techniques can lead to breakthroughs in emerging quantum science and technology applications.@en

This brief presents a capacitively-biased CMOS voltage reference, which can operate from a sub-1V supply while achieving a low temperature coefficient (TC) and a competitive power-supply rejection ratio (PSRR). The reference voltage is generated by a capacitive bias circuit that provides a well-defined proportional-to-absolute-temperature (PTAT) bias current for a ΔVth type reference that consists of two stacked MOSFETs with different threshold voltages. The generated output voltage is sampled by an auto-zeroed (AZ) buffer, which can drive capacitive loads up to 2 nF. Fabricated in a 65 nm CMOS process, the prototype voltage reference occupies 0.058 mm2, including the AZ buffer and an on-chip timing generator. It outputs a reference voltage of 204.1 mV with a minimum supply voltage of 0.7 V. It achieves a TC of 18 ppm/° C from -40 ° C to 85 ° C and a PSRR of -75 dB at 100 Hz with only 200 μV ripple.

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