High-power, broadband terahertz radiation from large area plasmonic photoconductive emitters operating at telecommunication optical wavelengths

We present a high-power, broadband terahertz emitter that operates at telecommunication optical pump wavelengths at which high-performance and compact fiber lasers are commercially available. The presented terahertz emitter is a novel large area photoconductive emitter fabricated on a high resistivity ErAs:InGaAs substrate that utilizes a two-dimensional array of plasmonic nano-antennas. By incorporating plasmonic nano-antennas, stronger dipole moments are induced in response to an incident optical pump beam and, therefore, higher optical-to-terahertz conversion efficiencies are achieved compared to the state-of-the art. We demonstrate terahertz radiation power levels as high as 300 µW over a 0.1–5 THz frequency range at a 400 mW optical pump power. This is the highest reported terahertz radiation power level from a photoconductive terahertz emitter operating at telecommunication optical pump wavelengths.