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14 March 2018 High-power pulsed terahertz radiation from terahertz nanoantenna arrays based on plasmonic nanocavities (Conference Presentation)
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We present a photoconductive terahertz source that offers broadband pulsed terahertz radiation with enhanced optical-to-terahertz conversion efficiencies compared to photoconductive terahertz sources based on short-carrier-lifetime semiconductors. The performance enhancement is achieved by utilizing a plasmonic nanocavity that tightly confines optical pump photons inside a photoconductive layer near the terahertz radiating elements. The plasmonic nanocavity is implemented by sandwiching the photoconductive layer between a distributed Bragg reflector and plasmonic metallic structures, which are optimized to be resonant at the optical pump wavelength. The plasmonic structures are also designed as a broadband terahertz nanoantenna array. A thin undoped GaAs film is used as the photoconductive layer offering much higher carrier drift velocities compared to short-carrier-lifetime GaAs substrates. The tight confinement of the optical pump photons and the use of a low-defect photoconductive semiconductor layer allow drift of almost all of the photo-generated carriers to the terahertz nanoantennas in a sub-picosecond time scale to efficiently contribute to pulsed terahertz radiation. We experimentally demonstrate that the presented terahertz source offers 60 times higher optical-to-terahertz conversion efficiency compared to a similar terahertz nanoantenna array fabricated on a short-carrier-lifetime semiconductor. We demonstrate pulsed terahertz radiation with powers exceeding 4 mW over 0.1-4 THz frequency range.
Conference Presentation
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Nezih Tolga Yardimci, Semih Cakmakyapan, Soroosh Hemmati, and Mona Jarrahi "High-power pulsed terahertz radiation from terahertz nanoantenna arrays based on plasmonic nanocavities (Conference Presentation)", Proc. SPIE 10531, Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications XI, 1053106 (14 March 2018);

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