Complete three-dimensional vector polarimetry with a Rydberg atom rf electrometer

TL;DR

This paper introduces a novel three-dimensional vector polarimeter based on Rydberg atom RF electrometry, capable of measuring the full polarization state of RF fields, including amplitude, phase, and polarization ellipse, with high precision.

Contribution

The work extends Rydberg atom RF sensors to full 3D polarization measurement using heterodyne detection with three orthogonal local oscillators, a novel approach in the field.

Findings

Achieved full 3D polarization measurement of RF fields.

Demonstrated accurate phase and amplitude detection for different field orientations.

Measured low amplitude noise levels and phase stability in the system.

Abstract

Radio frequency (rf) receivers using Rydberg atoms offer appealing features over classical sensors, such as their size, frequency tuning range, and lack of field absorption. In this work, we extend the application space by demonstrating a Rydberg atom rf polarimeter. Using rf heterodyne with three independent and orthogonal local oscillators, we are able to extract the polarization ellipse of the field in three dimensions, in addition to the total amplitude of the field. We use the relative phases and amplitudes of the three generated heterodyne signals to measure the field amplitudes and phases along three cardinal axes giving the full three-dimensional polarization. We demonstrate this polarization measurement for incoming fields at different angles around the sensor. Lastly, we investigate the reception of data symbols encoded in the horizontal and vertical signal field polarizations and the phase between them. Our measurements yield an amplitude noise of 57 $\mu$V/m/$\sqrt{\text{Hz}}$ for horizontal polarization, 66 $\mu$V/m/$\sqrt{\text{Hz}}$ for vertical polarization, and a standard deviation of 0.094 rad in the phase between the field components.