Terahertz radiation has many unique applications in imaging and sensing currently limited by low efficiency, complexity, and bulky nature of existing terahertz emitters. In this study, we propose an innovative terahertz emitter based on plasmonic nanowire light absorbers that can convert optical beam to terahertz radiation with unprecedented conversion efficiencies. By utilizing nanowire arrays integrated with plasmonic nano-antennae, we confine the majority of the incident optical photons within nanoscale distances from metal contacts. As a result, the majority of the photo-generated carriers quickly drift to the plasmonic nano-antennae in a sub-picosecond time-scale and contribute to efficient terahertz generation. It is predicted that bias-free terahertz emitters based on this novel device architecture can achieve tens of mW terahertz radiation power levels and optical-to-terahertz conversion efficiencies as high as 24%. Additionally, the proposed terahertz emitters operate at telecommunication optical wavelengths and are monolithically integrated on Si or InP substrates, offering a compact and low-cost device platform.
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