Fabry-Perot cavity resonance enabling highly polarization-sensitive double-layer gold grating

Abstract

We present experimental and theoretical investigations on the polarization properties of a single- and a double-layer gold (Au) grating, serving as a wire grid polarizer. Two layers of Au gratings form a cavity that effectively modulates the transmission and reflection of linearly polarized light. Theoretical calculations based on a transfer matrix method reveals that the double-layer Au grating structure creates an optical cavity exhibiting Fabry-Perot (FP) resonance modes. As compared to a single-layer grating, the FP cavity resonance modes of the double-layer grating significantly enhance the transmission of the transverse magnetic (TM) mode, while suppressing the transmission of the transverse electric (TE) mode. As a result, the extinction ratio of TM to TE transmission for the double-layer grating structure is improved by a factor of approximately 8 in the mid-wave infrared region of 3.4–6 μm. Furthermore, excellent infrared imagery is obtained with over a 600% increase in the ratio of the TM-output voltage (Vθ = 0°) to TE-output voltage (Vθ = 90°). This double-layer Au grating structure has great potential for use in polarimetric imaging applications due to its superior ability to resolve linear polarization signatures.

Dichroic Optical Diode Transmission in Two Dislocated Parallel Metallic Gratings

“…The thickness of the optical diode structure proposed in this paper is as small as 160 nm. With the development of nanofabrication technologies, many methods can be applied to the fabrication of metallic gratings structures, such as ultraviolet nanoimprint lithography [32], laser-direct-writing lithography [33], and electron-beam lithography [34]. The optical diode character is independent of the incident intensity.…”

Poly(sulfur-random-(1,3-diisopropenylbenzene)) based mid-wavelength infrared polarizer: Optical property experimental and theoretical analysis

“…The discrepancy in transmission intensities may be induced by the imperfections and errors in the fabrication that were mentioned above. For a better understanding of the response of the bilayer Au-SPG film on silicon wafer, the transmission and reflection of the composite structure were analyzed with a multiple-layer model based on the transfer matrix method [38,[44][45][46]. The overall transfer matrix (…”

“…The cross-sections of Au-SPG were characterized with the scanning electron microscope (SEM, JEOL 7800F). Numerical simulations using CST Microwave Studio and COMSOL Multiphysics, which use the finite integration technique (FIT) [37,38] and the finite element method (FEM) [39][40][41], respectively, were carried out to obtain the solution of Maxwell's equation. In the simulation, = 3.4 and = 1.9 were used for the refractive indices for silicon and SPG, respectively.…”

Broadband Polarization‐Insensitive Coherent Rasorber in Terahertz Metamaterial with Enhanced Anapole Response and Coupled Toroidal Dipole Modes

“…The condition of FP resonance can be expressed by Equation () where γ is the round‐trip propagation phase, Φ( r 21 ) and Φ( r 23 ) are the phases of the reflection coefficients at the back of upper FSS and the front of the lower FSS, β is the propagation phase factor in the air layer. [ 56 ] As γ is equal to the integer multiple of 2π, the constructive interference can be excited inside the air spacer between the upper and lower FSSs. The FP resonance occurs at f 3 = 3.3 THz (shown in Figure 2d) when the height of the air spacer is selected as h = 14 µm, where the transmission is greatly strengthened due to the maximum reduction of the refection by destructive interference.…”