Universal optical electric-field sensor covering frequencies from 10 to 100 GHz

This article describes an optical sensor that can accurately measure electric-field strength at frequencies ranging from 10 to 100 GHz. The optical sensor utilizes a 1 mm × 1 mm × 1 mm CdTe crystal mounted on the tip of an optical fiber, which theoretically possesses the potential to cover the frequency band from several megahertz to terahertz. A free-space electric-field measurement demonstrates its flat frequency response within a 6-dB range from 10 to 50 GHz. The sensitivity increases due to the resonance of the radio frequency wave propagating in the crystal at the frequencies higher than 50 GHz. The optical sensor can accurately measure the distribution of the electric field radiated from a horn antenna at 100 GHz.