Light transmission through metallic channels much smaller than the wavelength

Transmission and reflection through 1D metallo-dielectric gratings of real metals under sub-wavelength condition

“…(2) that there are infinite number of solutions of this equation and each of these solutions is called a waveguide mode. However, when w < λ/2 with n g = 1, only the fundamental waveguide mode is propagating inside a slit cavity [1][2][3]. In this case, given that |n 2 r | >> |n 2 Ef f |, n Ef f of the fundamental mode can be expressed as Eq.…”

“…After the discovery of Extraordinary Optical Transmission (EOT) through 1D metallo-dielectric gratings, a number of efforts, both numerical and semianalytical, has been undertaken to understand the physics behind this exceptional phenomenon [1][2][3][4][5][6][7][8][9]. Numerical approaches of modeling EOT devices include the transfer matrix formalism [1,5,10,11], the Finite Difference Time Domain (FDTD) method [9,12], the Rigorous Coupled Wave Analysis (RCWA) [3,6,8,13], and the Exact Modal Analysis (EMA) [14].…”

“…However, the transfer matrix formalism and the FDTD method are computationally very demanding [15]. In contrast, the RCWA and the EMA are the two closely related numerical techniques which are widely used to analyze 1D structures [2,3,5,6,8,16]. The RCWA expresses the dielectric function of the overall grating structure and the Electromagnetic (EM) field inside the grating region (−h ≤ z ≤ 0, see Fig.…”

Resonant backward scattering of light by a subwavelength metallic slit with two open sides

“…1,2, 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39 ). In the last few years, a great number of studies have been devoted to the nanostructures in metal films, namely a single aperture, a grating of apertures and an aperture surrounded by grooves.…”

“…9,10,11,12,13 At the resonant wavelengths, the transmitted field increases via the strong coupling of an incident wave with the waveguide modes giving a Fabry-Perot-like behavior. 10,13,14,15 In the case of films, whose thickness are too small to support the intra-cavity resonance, the extraordinary transmission can be caused by another mechanism, the generation of resonant surface plasmon polaritons and coupling of them into radiation. 4,9,11,16,22 Both physical mechanisms play important roles in the extraordinary transmission through arrays of two-side-open slits (transmission gratings) and the resonant reflection by arrays of oneside-open slits (reflection gratings).…”