Rydberg-based Electric Field Sensor

To address the DARPA need for an SI-traceable, self-calibrating, high-precision electric field sensor in the RF, microwave, and millimeter-wave regimes, Physical Optics Corporation (POC) proposes to develop a new Rydberg-based Electric Field Sensor (REFS). This proposed REFS solution is based on a miniaturized alkali vapor cell with an active volume of 0.05 x 0.05 x 0.05 mm^3 and low-SWaP external-cavity diode laser systems. Specifically, the innovation in the miniaturization of alkali vapor cells will enable the REFS device to measure rapidly oscillating electric fields with unprecedented spatial resolution (~0.01 mm) without distorting the field to be measured. As a result, the REFS technology offers an SI-traceable electric field sensor with superb spatial resolution and a broadband operation capability in portable packaging (volume: 10 x 5 x 25 mm^3 (probe module) and 8 x 5 x 12 in.^3 (laser module)), which directly address the DARPA requirements. In Phase I, POC will demonstrate the feasibility of the REFS technology by fabricating miniaturized rubidium vapor cells, measuring an absorption spectrum, and implementing key laser systems, to reach Technology Readiness Level (TRL)-4. In Phase II, POC plans to enhance, optimize, and ruggedize the REFS technology to meet all of DARPAs requirements and reach TRL-6.