Modal method for conical diffraction on a rectangular slit metallic grating in a multilayer structure

Abstract

The modal method is applied to the problem of conical diffraction on a rectangular slit metallic grating lying on an arbitrary multilayer medium. In the approximation of the surface impedance boundary condition on the grating walls, a single matrix equation is obtained, whose coefficients are expressed simply by the reflectivities on the different layers. A simple and comprehensive treatment is thus obtained for virtually any multilayer system. The method is illustrated for the case of a cavity formed by a planar metallic mirror and a grating, as well as the system formed by a doped layer with Drude susceptibility in a substrate below the grating. The method could be useful for the design of near- and far-infrared devices.

Strong Light-Matter Coupling in Subwavelength Metal-Dielectric Microcavities at Terahertz Frequencies

“…This picture is consistent with an electromagnetic model, presented in Ref. [18], which reproduces well the reflection curves (blue straight line) [19]. The lateral Fabry-Perot effect arises because of the strong impedance mismatch between the single-metal and double-metal regions which carry the TM 0 mode.…”

“…The grating period p is smaller than the wavelength of the incident light, and hence the only diffracted order is the 0th order specular reflection. The dips indicate resonant absorption of the incident radiation due to the excitation of cavity modes [17,18]. The features between 8 and 9 THz are related to the reststrahlen band of the semiconductor.…”

Purcell Enhancement of Spontaneous Emission from Quantum Cascades inside Mirror-Grating Metal Cavities at THz Frequencies

“…Details of the model can be found in Refs. [14,15]. In this framework both the product ext ÿ sp and ÿ sp can be evaluated independently.…”

Near field and cavity effects on coupling efficiency of one-dimensional metal grating for terahertz quantum well photodetectors

“…23 coupled THzQWP is shown in Fig. This method can treat a general diffraction problem of a rectangular slit metallic grating on top of an arbitrary multilayered system, which is detailed in Ref.…”

“…Many theoretical investigations have also been carried out to improve the coupling efficiency. 22 In this paper, the effect of 1D metal grating is systematically studied with the modal method proposed by Todorov et al, 23 and the coupling efficiency is investigated for different grating periods. 19 Although QWIP FPAs are commercially available, large-format array detectors in the THz range are still lacking.…”