# Reconstruction-free quantum sensing of arbitrary waveforms

## TL;DR

This paper introduces a quantum sensing protocol using spin echoes to directly detect arbitrary time-dependent magnetic waveforms with high temporal resolution and sensitivity, applicable to nitrogen-vacancy centers in diamond.

## Contribution

The authors develop a reconstruction-free quantum sensing method that enables direct detection of arbitrary waveforms with improved temporal resolution and sensitivity.

## Key findings

- Achieved ~20 ns time resolution in waveform detection.
- Demonstrated field sensitivity of ~4 μT/√Hz.
- Validated the method with nitrogen-vacancy centers in diamond.

## Abstract

We present a protocol for directly detecting time-dependent magnetic field waveforms with a quantum two-level system. Our method is based on a differential refocusing of segments of the waveform using spin echoes. The sequence can be repeated to increase the sensitivity to small signals. The frequency bandwidth is intrinsically limited by the duration of the refocusing pulses. We demonstrate detection of arbitrary waveforms with $\sim 20 {\rm ns}$ time resolution and $\sim 4\mu{\rm T}/\sqrt{\rm Hz}$ field sensitivity using the electronic spin of a single nitrogen-vacancy center in diamond.