Plasmonics-enhanced THz emitters: new designs and approaches
Igor A. Glinskiy,1,2 Denis V. Lavrukhin,1,2 Alexander E. Yachmenev,1,2 Rustam A. Khabibullin,1,2 Nikolay V. Zenchenko,1,3 Dmitry S. Ponomarev,1,2 1 Institute of Ultra High Frequency Semiconductor Electronics of RAS, Moscow, Russia 2 Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia 3 Bauman Moscow State Technical University, Moscow, Russia
Abstract
Existing THz sources do not meet many challenges posed by the rapidly developing THz science and technology and improving the efficiency of the THz emitters still remains challenging. Photoconductive antennas (PCAs) are prevalent THz emitters widely used in the THz spectroscopy and imaging due to their reliability, cost effectiveness and a relative ease of fabrication. Recently we developed and fabricated a plasmon-assisted THz PCA efficiently operating with low-power optical pumps. The PCA utilizes a record 100 nm height plasmonic grating resulted in the 3000-fold enhancement in the emitted THz power and the 25-fold increase in the THz photocurrent compared to the conventional PCA without the grating. Here we report on optimization of structure of plasmonic grating to ensure maximum transmittance when exposed to laser radiation λ0 = 800 nm. The maximum transmittance, equal to 85%, is achieved at an electrode width w = 100 nm, a gap between electrodes g = 120 nm, and height h = 170 nm. The optimal thickness of the antireflection dielectric layer located above the metal structure was determined, at which the minimum reflection is observed for the general design of the PCA. The use of 120 nm thick Al2O3 dielectric layer allows the reflection coefficient to be reduced to 26%. It is expected that use of this structure will additional enhancement in the emitted THz power.
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Speaker
Glinskiy Igor
IUHFSE RAS
Russia
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