High-Power Terahertz Generation from Bias-Free, Telecommunication-Compatible Photoconductive Nanoantennas
We present a bias-free photoconductive terahertz emitter that operates at telecommunication optical pump wavelengths, at which low-cost and compact femtosecond fiber lasers are commercially available. Bias-free operation is enabled by a built-in electric field formed between the device contact electrodes and photoconductor substrate, and ensures a highly reliable operation by eliminating high photoconductor dark currents that are detrimental to the device reliability. Arrays of plasmonic nanoantennas are utilized as terahertz radiating elements to obtain a broadband terahertz radiation. We demonstrate terahertz radiation powers exceeding 0.25 mW over a 0.1–3.5 THz frequency range with a 90 dB dynamic range.