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In this paper, the surface plasmon resonance (SPR) of rectangular cavity is investigated in Ag-Si-SiO2 under near-infrared light incident by finite-difference time-domain (FDTD). Between the surface plasma and the thickness of the silver film, the length of the silver film, the thickness of silicon, and the position of silicon, these relationships will be studied in a rectangular cavity, which is surrounded by silver film, two rectangular nanoscale silicons, and silicon dioxide. The surface plasmon resonance of the RCM is independent of the distance between the two silicons when the transverse silver film length l is fixed and of height d = 10k (k = 1, 2, 3, 4, and 5) nm of rectangular silicon and thickness t (t = 6, 7, 8, 9, 10, 11, and 12 nm) of silver film while the length l = 600 nm. The SPR is a lateral length dependence of silver film. The plasma resonance of the two first-order modes is distributed symmetrically on both sides of the local field in RCM, and it is irrelevant with the position of the vibration mode and the thickness of the silver film. On the basis of the above research, we propose to create a guided-wave resonance that can be directly observed from the normal incidence transmission spectra and electric field distribution. This structure can be used as a highly tunable optical sensitive element that can be tuned with a small change of transverse silver film length. [ABSTRACT FROM AUTHOR]

We present a high-performance refractive index sensor based on Fano resonance with a figure of merit (FOM) about 56.5 in all-dielectric metasurface which consists of a periodically arranged silicon rings with two equal splits dividing them into pairs of arcs of different lengths. A Fano resonance with quality factor ~133 and spectral contrast ratio ~100% arises from destructive interference of two antiphase electric dipoles in the two arcs of the split-ring. We can turn on and/or off the Fano resonance with a modulation depth nearly 100% at the operating wavelength of 1067 nm by rotating the polarization of incident light. We believe that our results will open up avenues for the development of applications using Fano resonance with dynamically controllability such as biochemical sensors, optical switching, and modulator. [ABSTRACT FROM AUTHOR]

We present a multi-band terahertz absorber formed by periodic square metallic ribbon with T-shaped gap and a metallic ground plane separated by a dielectric layer. It is demonstrated that absorption spectra of the proposed structure consist of four absorption peaks located at 1.12, 2.49, 3.45, and 3.91 THz with high absorption coefficients of 98.0, 98.9, 98.7, and 99.6%, respectively. It is demonstrated that the proposed absorber has the tunability from single-band to broadband by changing the length of square metallic ribbon and we can also select or tune the frequencies which we want to use by changing polarization angles. Importantly, the quality factor Q at 3.91 THz is 30.1, which is 5.6 times higher than that of 1.12 THz. These results indicate that the proposed absorber has a promising potential for devices, such as detection, sensing, and imaging. [ABSTRACT FROM AUTHOR]

In this paper, the surface plasmon resonance (SPR) of rectangular cavity is investigated in Ag-Si-SiO2 under near-infrared light incident by finite-difference time-domain (FDTD). Between the surface plasma and the thickness of the silver film, the length of the silver film, the thickness of silicon, and the position of silicon, these relationships will be studied in a rectangular cavity, which is surrounded by silver film, two rectangular nanoscale silicons, and silicon dioxide. The surface plasmon resonance of the RCM is independent of the distance between the two silicons when the transverse silver film length l is fixed and of height d = 10k (k = 1, 2, 3, 4, and 5) nm of rectangular silicon and thickness t (t = 6, 7, 8, 9, 10, 11, and 12 nm) of silver film while the length l = 600 nm. The SPR is a lateral length dependence of silver film. The plasma resonance of the two first-order modes is distributed symmetrically on both sides of the local field in RCM, and it is irrelevant with the position of the vibration mode and the thickness of the silver film. On the basis of the above research, we propose to create a guided-wave resonance that can be directly observed from the normal incidence transmission spectra and electric field distribution. This structure can be used as a highly tunable optical sensitive element that can be tuned with a small change of transverse silver film length. [ABSTRACT FROM AUTHOR]