Measurements of high-intensity radio-frequency electric fields with Rydberg vapors

Measurements of radio-frequency (RF) electric fields in the MHz- to sub-THz range using EIT spectroscopy of Rydberg states in atomic vapors have garnered significant interest in recent years. Here we describe recent work extending the approach to measurements of coherent high-intensity RF electric fields above 1 kV/m and continuous-frequency RF measurement capability. The spectra are modeled using a non-perturbative Flo-quet model that accounts for higher-order interactions and state mixing. The spectroscopic data also reveal nonlinear amplifier behavior and noise.