Broadband Generation of Terahertz Waves via Infrared Frequency Nondegenerate Parametric Down-Conversion by Nonlinear Graphene Arrays
Lerer A.M.(1), Makeeva G.S.(2), Cherepanov V.V.(1)
(1)Faculty of Physics, Southern Federal University, 5 Zorge Street, Rostov-on-Don, Russia 344090;
(2)Dept. of Radioengineering, Penza State University, 40 Krasnaya Street, Penza, Russia, 440026
Abstract
To analyze the THz wave generation by the mid-IR frequency nondegenerate parametric down-conversion process (NPDC) in the nonlinear graphene arrays, the nonlinear simulations using the perturbation method for solving the nonlinear diffraction problems were performed. First, we find the resonant frequencies of surface plasmon polaritons (SPP) modes in graphene nanoribbon arrays using calculated multimode linear absorption spectra of incident waves with s-, p-polarization. Then we select the graphene ribbon sizes to satisfy the excitation condition of the SPP modes in the mid-IR frequency range. We choice the pump and signal frequencies equal to resonant frequencies of the fundamental and high order SPP modes of the graphene arrays, respectively. Secondly, we obtain graphene SPPs by tuning the graphene chemical potential μс and simultaneously changing the frequencies of pump and signal waves according the tuned linear absorption spectrum. It is shown that the efficiency of THz wave generation via frequency NPDC of mid-IR to THz by nonlinear graphene arrays increases by several orders of magnitude when the frequency of signal and pump waves are close to the resonant frequencies. An optimal value of the chemical potential at which the maximum efficiency of NPDC mid-IR was determined. Using this method to generate THz waves the wide frequency tunability from 1.5 to 8.5 THz can be realized by tuning the pump frequency and the corresponding chemical potential from 0.25 to 1 eV.
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Speaker
Vladimir Cherepanov
Southern Federal University
Russia
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