Theoretical analysis of enhanced nonlinear conversion from metallo-dielectric nano-structures

International audienceA new configuration of sub-wavelength silver coaxial apertures filled with Lithium Niobate (LN) is proposed to enhance the Second Harmonic Generation (SHG) in transmission mode. The chosen geometrical parameters allows having both TE11 guided mode excitation for local field confinement of the fundamental signal and Fabry-Perot high transmission of the SH wave. Furthermore, an implementation of the three-dimensional Finite Difference Time Domain (3D-FDTD) method for nonlinear optical simulation is described. This method provides a direct calculation of the nonlinear polarizations before calculating the nonlinear electric and magnetic fields. FDTD studies shows that by embedding metallic nanostructures, for exciting TE11 like-mode inside a nonlinear material (LN), we achieve a SH signal 27 times higher than that generated on unpatterned LN