Fabrication and Characterization of a Metallic–Dielectric Nanorod Array by Nanosphere Lithography for Plasmonic Sensing Application

Abstract

In this paper, a periodic metallic–dielectric nanorod array which consists of Si nanorods coated with 30 nm Ag thin film set in a hexagonal configuration is fabricated and characterized. The fabrication procedure is performed by using nanosphere lithography with reactive ion etching, followed by Ag thin-film deposition. The mechanism of the surface and gap plasmon modes supported by the fabricated structure is numerically demonstrated by the three-dimensional finite element method. The measured and simulated absorptance spectra are observed to have a same trend and a qualitative fit. Our fabricated plasmonic sensor shows an average sensitivity of 340.0 nm/RIU when applied to a refractive index sensor ranging from 1.0 to 1.6. The proposed substrates provide a practical plasmonic nanorod-based sensing platform, and the fabrication methods used are technically effective and low-cost.

A Nanosensor Based on a Metal-Insulator-Metal Bus Waveguide with a Stub Coupled with a Racetrack Ring Resonator

“…The magnetic field enhancements mainly arose from the superposition of the incident SPPs with the reflected SPPs at the boundary of the air and metal intersurface structure. This phenomenon is important for the design of plasmonic sensors where larger magnetic field intensities are desired [ 40 ]. The structure parameters are fixed as L = 200 nm, h = 100 nm, R = 140 nm, r = 90 nm, g = 10 nm, except the displacement of the ring from the stub x .…”

“…Especially, when x = 100 nm, the near-field intensity pattern strongly localized at the racetrack ring resonator with respect to H Z at other structures, which can be seen from the effectively localized magnetic field. The discrepancy of the resonance dip at a different transmittance is due to the different coupling position where different interferences of near-field coupling effect [ 40 ] and phase coupling effect [ 40 ] occur between the incident SPPs and the racetrack ring resonator. According to the above analysis, we can see that we can change x to obtain different transmittances and a normalized H Z field.…”

Perfect Absorption and Refractive-Index Sensing by Metasurfaces Composed of Cross-Shaped Hole Arrays in Metal Substrate

“…Figure 7b shows the dependence of the position of the absorption peak on the refractive index. Conventionally, two important parameters, sensitivity (S) and figure of merit (FOM), are widely used to estimate the sensing performance [80][81][82][83][84]. S and FOM can be defined as:…”

“…Figure 7 b shows the dependence of the position of the absorption peak on the refractive index. Conventionally, two important parameters, sensitivity ( S ) and figure of merit ( FOM ), are widely used to estimate the sensing performance [ 80 , 81 , 82 , 83 , 84 ]. S and FOM can be defined as: where Δλ is the spectral shift of the absorption peak, Δ n is the change of the refractive index, and FWHM is the full width at half maximum of the perfect absorption peak.…”

Polarization-Insensitive Hybrid Plasmonic Waveguide Design for Evanescent Field Absorption Gas Sensor

“…Plasmonic WGs propagate the surface plasmons wave at the dielectric-metal interface which is evanescently confined in the direction perpendicular to the propagation [20][21][22]. These WGs can confine the light to the subwavelength region as their light confining ability is not affected by the diffraction limit [23]. However, these WGs put up with high propagation loss due to the presence of the metal as the main building block of the WG [24].…”