Rydberg-atom-based system for benchmarking millimeter-wave automotive radar chips

Rydberg atomic sensors and receivers have enabled sensitive and traceable measurements of rf fields at a wide range of frequencies. Here, we demonstrate the detection of electric field amplitude in the extremely-high-frequency (EHF) band, at <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><a:mn>131</a:mn><a:mspace width="0.2em"/><a:mi>GHz</a:mi></a:math>. In our approach, we propagate the EHF field in a beam, with control over its direction and polarization at the detector using photonic wave plates. This way, we take advantage of the highest detection sensitivity, registered for collinear propagation and circular polarization. To exhibit the potential for applications in this kind of Rydberg-atom-based detection, we perform test measurements on the EHF field emitted from an on-chip radar, which is designed to be used in the automotive industry as a vital sign detector. Our work elucidates practical applications of Rydberg-atom media and photonic metamaterial elements. Published by the American Physical Society 2024