THz Generation using Nonlinear Optics: Mathematical Analysis and Design of THz antennas

Abstract

In this paper, a mathematical model is designed for THz generation from a nonlinear random medium. Using nonlinear optics and Maxwell’s equations a set of nonlinear wave equations are derived to give scattered electromagnetic fields from an inhomogeneous medium. First, the analysis is done with second order nonlinearity. Its scattering parameters are calculated for THz radiation. Secondly, third order nonlinearity is described in terms of the coupling of Scalar and vector field components of nonlinear wave equations. The coupling of waves results in soliton generation. Multiple nonlinear interaction in the medium also gives wide bandwidth. Speed and high bandwidth is a demand of future networks. Hence a mathematical proof is implemented for THz antennas using SHG (Second harmonic generation) and THG (Third harmonic generation) materials. These antennas are designed and simulated using GaAs as a SHG material, and Graphene with SiO2 substrate as a THG material. GaAs is used as a substrate, which radiates at 524.8 GHz giving a high bandwidth of 25 GHz. Similarly, Graphene patch antenna with SiO2 substrate radiates in THz region at 3.5THz giving very high bandwidth of 2.5THz.

Parameter Estimation of an Inhomogeneous Medium by Scattered Electromagnetic Fields Using Nonlinear Optics and Wavelets

“…A set of equations from (96) to (101) are used to find the inner product solutions. Scattered electromagnetic wave from self-phase modulated data [13] is used which is a nonlinear scattered electromagnetic wave. Using E and H fields from these second order nonlinear waves and defining threedimensional wavelet basis functions for susceptibility, we get the set of equations.…”

“…In the first experiment, we assume χ e & χ m a matrix and calculate the scattered outputs. In our earlier work, this has been taken as centrosymmetric and noncentrosymmeric matrices, and the scattered outputs were calculated [13]. First order scattered fields E 1 and H 1 and second order scattered fields E 2 and H 2 are calculated ( Figure 1 [13]) using Maple.…”

“…Basis function Daubchies wavelet (see Figure 1) is designed in Matlab and in Maple (see Figure 2). Initially the scattered electromagnetic fields are E 1 , E 2 simulated in Maple [13].…”