Phase sensitive quantum spectroscopy with high frequency resolution

TL;DR

This paper introduces a quantum spectroscopy method using a single diamond spin that achieves high frequency resolution and nanoscale spatial precision, enabling detailed signal reconstruction at GHz frequencies.

Contribution

The authors develop a novel measurement protocol for quantum probes that combines high frequency resolution with nanoscale spatial sensitivity, surpassing traditional quantum sensors.

Findings

Achieved 58 nT/√Hz amplitude sensitivity

Achieved 0.095 rad/√Hz phase sensitivity

Demonstrated 10^-12 frequency uncertainty at 1.51 GHz

Abstract

Classical sensors for spectrum analysis are widely used but lack micro- or nanoscale spatial resolution. On the other hand, quantum sensors, capable of working with nanoscale precision, do not provide precise frequency resolution over a wide range of frequencies. Using a single spin in diamond, we present a measurement protocol for quantum probes which enables full signal reconstruction on a nanoscale spatial resolution up to potentially 100\,GHz. We achieve $58\,\mathrm{nT/\sqrt{Hz}}$ amplitude and $0.095\,\mathrm{rad/\sqrt{Hz}}$ phase sensitivity and a relative frequency uncertainty of $10^{-12}$ for a $1.51\,\mathrm{GHz}$ signal within $10\,\mathrm{s}$ of integration. This technique opens the way to quantum spectrum analysis methods with potential applications in electron spin detection and nanocircuitry in quantum technologies.