When strongly pumped at twice their resonant frequency, non-linear resonators develop a high-amplitude intracavity field, a phenomenon known as parametric self-oscillations. The boundary over which this instability occurs can be extremely sharp and thereby presents an opportunity for realizing a detector. Here we operate such a device based on a superconducting microwave resonator whose non-linearity is engineered from kinetic inductance. The device indicates the absorption of low-power microwave wavepackets by transitioning to a self-oscillating state. Using calibrated wavepackets we measure the detection efficiency with zeptojoule energy wavepackets. We then apply it to measurements of electron spin resonance, using an ensemble of 209Bi donors in silicon that are inductively coupled to the resonator. We achieve a latched-readout of the spin signal with an amplitude that is five hundred times greater than the underlying spin echoes.
@article{arxiv.2311.03702,
title = {Latched Detection of Zeptojoule Spin Echoes with a Kinetic Inductance Parametric Oscillator},
author = {Wyatt Vine and Anders Kringhøj and Mykhailo Savytskyi and Daniel Parker and Thomas Schenkel and Brett C. Johnson and Jeffrey C. McCallum and Andrea Morello and Jarryd J. Pla},
journal= {arXiv preprint arXiv:2311.03702},
year = {2023}
}