Simultaneous Reception, Demodulation, and Angle-of-Arrival Determination of Standard Communication Signals Using a Rydberg Atom-Based Sensor

Given their large dipole moments, high polarizability, and long excited state lifetimes, Rydberg atoms serve as excellent radio-frequency (RF) electric field sensors. In this talk, I will discuss the design and demonstration of a Rydberg atom-based receiver which we call a dual ladder Rydberg receiver. To construct the dual ladder receiver, we use two spatially overlapped but otherwise independent Rydberg receivers. We achieve this by accessing different Doppler classes through the use of frequency detuned laser beams, setting the local oscillator (LO) fields of each receiver 90 degrees out of phase with one another, and matching the polarization of the LO fields with the optical polarizations. While typical Rydberg receivers rely on RF-heterodyne detection to receive a modulated RF signal, the dual ladder design instead utilizes RF-homodyne detection in order to simultaneously receive and directly output the in-phase (I) and quadrature (Q) components of the signal. As such, the dual ladder design forgoes post-processing requirements imposed by RF-heterodyne based receivers, namely, the need to remove negative frequency components of the signal and mix the signal down to baseband. Using the dual ladder design, we demonstrate reception and direct baseband readout of 16 quadrature amplitude, quadrature phase-shift keying, and amplitude phase-shift keying modulated signals. We further show that the inherent polarization sensitivity of this design enables the determination of the signal's angle of arrival through a single measurement, a capability not feasible using a typical Rydberg receiver.