Optics and Spectroscopy, 2024 Volume 132, Issue 1,Pages 105–110(Mi os1145)
Conference "Ultrafast Optical Phenomena (Ultra fast Light-2023)" October 2-4, 2023, Lebedev Institute of Physics, Russian Academy of Sciences Ultraviolet, infrared, and terahertz optics
Efficient THz emission by a photoconductive emitter with tight photocarrier confinement within high-aspect ratio plasmonic electrodes
Abstract:
We propose, simulate and investigate how the thickness of plasmonic electrode h and the ratio between h and the period of subwavelength periodical metallic (plasmonic) grating $h/p$ on the THz emission efficiency in a photoconductive emitter. By numerical optimization we determine the grating geometry with respect to maximal optical transmission. We showcase that simultaneous increase in $h$ and $h/p$ allows efficient excitation of plasmon modes in the grating, that follows with an THz power enhancement up to 10000 compared to conventional emitter without grating. The overall THz power exceeds 5 $\mu$W in the 0.1–4 THz bandwidth, with the conversion efficiency of $\sim$0.2%. The developed grating design can be also used for photoconductive THz detectors in modern THz spectroscopic and imaging setups.
Keywords:terahertz science and technology, terahertz pulsed spectroscopy, terahertz element base, photoconductive antenna, plasmonic grating, optical light confinement, semiconductors.