High-Sensitivity Plasmonic Photoconductive Terahertz Detector Driven by a Femtosecond Ytterbium-Doped Fiber Laser

Abstract

We introduce a high-sensitivity photoconductive terahertz detector that operates at ~1 µm optical pump wavelengths at which high-power Ytterbium-doped fiber lasers are available. Unlike conventional photoconductive detectors that utilize short-carrier-lifetime photoconductive substrates, the introduced detector uses an array of plasmonic nanoantennas to provide a sub-picosecond transport time for the majority of photocarriers generated by the optical pump beam. By preventing the recombination of the photocarriers and utilizing a higher mobility photoconductive substrate, the introduced detector offers significantly higher terahertz detection sensitivities compared to previously demonstrated photoconductive detectors based on short-carrier-lifetime photoconductive substrates. We demonstrate high-sensitivity terahertz detection at ~1 µm optical pump wavelengths with a record-high signal-to-noise-ratio of 95 dB over a 4 THz bandwidth.