VHF/UHF detection using high angular momentum Rydberg states

We demonstrate resonant detection of rf electric fields using electromagnetically induced transparency in 87Rb with L=3 to L'=4 Rydberg states. These Rydberg states are accessible with three-photon infrared optical excitation. By reducing the rf carrier frequency from the GHz range, these Rydberg states enable a broader class of electrically small atomic receivers. We assess sensitivity limits and prospects for further reduction of on-resonant carrier frequencies.