Massachusetts Institute of Technology

Jonah A Majumder

John Francis Barry

Danielle Ann Braje

Linh M Pham

Michael F O'Keeffe

Erik R Eisenach

Christopher Louis Panuski

Isaac Chuang

Erik M Thompson

Matthew Steinecker

Jessica Kedziora

Xingyu Zhang

Jennifer Schloss

Peter Moulton

We have developed a high-performance, low-volume, low-weight, and low-power sensor based on a self-sustaining oscillator. The techniques described here may be used for sensing various fields; we demonstrate magnetic sensing. The oscillator is based on a dielectric resonator that contains paramagnetic defects and is connected to a sustaining amplifier in a feedback loop. The resonance frequency of the dielectric resonator shifts in response to changes in the magnetic field, resulting in a shift in the frequency of the self-sustaining oscillator. The value of the magnetic field is thereby encoded in the shift or modulation output of the self-sustaining oscillator. The sensor as demonstrated uses no optics, no input microwaves, and, not including digitization electronics, consumes less than 300 mW of power and exhibits a sensitivity at or below tens of pT/√{square root over (Hz)}. In some implementations, the sensor is less than 1 mL in volume.

Oscillator-based solid-state spin sensor

Microwave resonator readout of the cavity-spin interaction between a spin defect center ensemble and a microwave resonator yields fidelities that are orders of magnitude higher than is possible with optical readouts. In microwave resonator readout, microwave photons probe a microwave resonator coupled to a spin defect center ensemble subjected to a physical parameter to be measured. The physical parameter shifts the spin defect centers' resonances, which in turn change the dispersion and/or absorption of the microwave resonator. The microwave photons probe these dispersion and/or absorption changes, yielding a measurement with higher visibility, lower shot noise, better sensitivity, and higher signal-to-noise ratio than a comparable fluorescence measurement. In addition, microwave resonator readout enables coherent averaging of spin defect center ensembles and is compatible with spin systems other than nitrogen vacancies in diamond.

Microwave resonator readout of an ensemble solid state spin sensor

Growing community of inventors

Cambridge, MA, United States of America

Jonah A Majumder