Time-resolved sensing of electromagnetic fields with single-electron interferometry

TL;DR

This paper introduces a single-electron interferometry-based quantum sensor capable of high-resolution, time-resolved detection of microwave electromagnetic fields, including their quantum fluctuations, with potential for on-chip quantum radiation detection.

Contribution

The work presents a novel interferometry technique using a single-electron wavefunction to measure time-dependent electric fields and their quantum fluctuations with high temporal and voltage resolution.

Findings

Achieved a temporal resolution of tens of picoseconds.

Demonstrated voltage resolution of a few tens of microvolts.

Proved simultaneous measurement of field amplitude and quantum fluctuations.

Abstract

Characterizing quantum states of the electromagnetic field at microwave frequencies requires fast and sensitive detectors that can simultaneously probe the field time-dependent amplitude and its quantum fluctuations. In this work, we demonstrate a quantum sensor that exploits the phase of a single electron wavefunction, measured in an electronic Fabry-Perot interferometer, to detect a classical time-dependent electric field. The time resolution, limited by the temporal width of the electronic wavepacket, is a few tens of picoseconds. The interferometry technique provides a voltage resolution of a few tens of microvolts, corresponding to a few microwave photons. Importantly, our detector simultaneously probes the amplitude of the field from the phase of the measured interference pattern and its fluctuations from the interference contrast. This capability paves the way for on-chip detection of quantum radiation, such as squeezed or Fock states.