High-Resolution Near-Field Imaging and Far-Field Antenna Measurements with Atomic Sensors

Measurements of radio-frequency (RF) electric fields using atomic sensors based on quantum-optical spectroscopy of Rydberg states in vapors has garnered significant interest in recent years for the establishment of atomic standards for RF electric fields and towards the development of novel RF sensing instrumentation. Here we describe recent work employing atomic sensors for sub-wavelength near-field imaging of a K _u - band horn antenna. We demonstrate near-field imaging capability at a spatial resolution of λ/10 and measurements over a 72 to 240 V/m field range using off-resonance AC-Stark shifts of a Rydberg-atom resonance. A fiber-coupled atomic-sensor probe is also employed in far-field measurements of a WR-90 standard gain horn.