Studying and Simulation for Different Geometry of Nanoholes Array (NHA) in Surface Plasmons Biosensor (original) (raw)
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International Journal of Electrical and Computer Engineering (IJECE), 2020
The possibility to limit and manipulate photons at nanometer scales attracted a lot of interest for exciting applications from subwavelength in laser, biosensors, biomedical and optoelectronics devices, the sensor optical properties, however; are complex due to two resonances through propagating and localized surface plasmons. The optical properties of surface plasmons (SPs) at the resonant wavelength is depending on the geometrical nanostructure of materials. In this article, we used different geometry of nanoholes array, 4 and 9 nanoholes array in a metallic film gold nanoparticle with different thickness (20,50,100) nm on SiO2 substrate with refractive index 1.46, we designed two different geometries; 4-holes: hole radius r1=200 nm, period p1=600 nm; and 9-holes: r2=100 nm, period p2=300 nm. Transmission and reflection spectrum have been calculated and simulated by FDTD Lumerical program. From results are observed the effect of thickness is interesting, transmission is increased at (t=20nm) for two arrays. Furthermore, the number of hole and its area has an influence on optical transmission and other parameters (E, H, Ref) which are characteristics of design of metallic nanostructure. We can see that there is a peak value of the wavelength at 519 nm approximately to 73% strong light transmission with 4-NHA in the other hand wavelength of 519 nm transmission is 45% with 9-NHA. strong light transmission is hopeful for many applications (biomedical devices, nanoantennas and laser optical fiber).
The surface plasmon resonance of metal-film nanohole arrays
Solid State Communications, 2008
In this paper we investigated the enhanced transmission and surface plasmon resonance through a thin gold film with a periodic array of subwavelength nanoholes. Both freestanding gold-film nanohole arrays and gold-film nanohole arrays deposited on a gallium arsenide (GaAs) substrate are considered. Periodic arrays of nanoholes exhibit two different surface plasmon resonance features: localized waveguide resonance and the well-recognized photonic crystal resonance. The tangential electric field component E y is nonzero only in the hole region for a freestanding gold-film nanohole array, but it can exist in the hole region and in the metallic region for a gold-film nanohole array deposited on a GaAs substrate.
Optical Response of Plasmonic Nanohole Arrays: Comparison of Square and Hexagonal Lattices
Plasmonics, 2015
Nanohole arrays in metal films allow extraordinary optical transmission (EOT); the phenomenon is highly advantageous for biosensing applications. In this article, we theoretically investigate the performance of refractive index sensors, utilizing square and hexagonal arrays of nanoholes, that can monitor the spectral position of EOT signals. We present nearand far-field characteristics of the aperture arrays and investigate the influence of geometrical device parameters in detail. We numerically compare the refractive index sensitivities of the two lattice geometries and show that the hexagonal array supports larger figure-of-merit values due to its sharper EOT response. Furthermore, the presence of a thin dielectric film that covers the gold surface and mimics a biomolecular layer causes larger spectral shifts within the EOT resonance for the hexagonal array. We also investigate the dependence of the transmission responses on hole radius and demonstrate that hexagonal lattice is highly promising for applications demanding strong light transmission.
2013
Surface plasmon resonance platforms, based on arrays of nanoholes on gold films, were used to detect the binding of organic and biological molecules. Optical sensors were assembled using nanohole arrays with different resonance energies, tuned by adjusting the distance between the holes. A direct relationship between plasmon energy and bulk sensitivity to refractive index changes was verified experimentally. The highest sensitivity (ca. 463 nm/RIU) was obtained for the (1,0) SPP mode, excited on an array of nanoholes with 455 nm periodicity. Real-time monitoring of the specific biotin-streptavidin binding was also used to demonstrate the influence of transmitted light intensity and FWHM on the sensor performance.
Nanohole Plasmons in Optically Thin Gold Films
The Journal of Physical Chemistry C, 2007
The optical properties of single nanoholes in optically thin (t=20 nm) gold films on glass have been studied experimentally and theoretically. The measured elastic scattering spectra from the nanoholes exhibit a broad resonance in the red part of the visible spectrum, which is qualitatively similar to localized surface plasmon (LSP) resonances in gold nanodisks. The hole resonance red-shifts with increasing hole diameter (D=60-107 nm), similar to particle LSP resonances. These features could be well reproduced by electrodynamic simulations based on the Boundary Element Method (BEM). Further, the electric field distribution around the resonant nanoholes, obtained from the BEM simulations, exhibits a clear electric dipole pattern. This confirms the assignment of the hole resonance to a dipolar LSP resonance mode. However, in comparison to Au nanodisks of similar size, the hole LSP resonance exhibits a shorter dephasing time (τ). This observation can be understood in terms of an additional decay channel that is dominated by the short wavelength anti-symmetric bound (a b) surface plasmon polariton (SPP) mode of the surrounding Au film. Experimental verification of the LSP-SPP coupling is obtained from near-field scanning optical microscopy images, which exhibit interference fringes due to SPP emission from the hole. The fringe periodicity corresponds to a SPP wavelength of λ a b ≈285 nm, much less than both the free space wavelength λ 0 =633 nm or the wavelength of the more well-known symmetric leaky mode.
Investigating the Optical Transmission Spectra of Plasmonic Spherical Nano-Hole Arrays
Plasmonic nano-structures are important for many photonic devices and applications. The optical transmission spectra of such structures are extraordinary. In this paper, we investigate the optical transmission spectra of thin gold films perforated with imperfect circular nano-hole arrays using the finite difference time domain (FDTD). It is observed that both of the intensity and resonance positions of the transmission spectra of perfect plasmonic circular nano-hole arrays are stronglymodified due to nano-holes imperfection. Furthermore, we comprehensively study the transmission spectrum of plasmonic spherical nano-hole arrays as a simple example for hole imperfection.
Nanohole Plasmons in Optically Thin
The optical properties of single nanoholes in optically thin (t=20 nm) gold films on glass have been studied experimentally and theoretically. The measured elastic scattering spectra from the nanoholes exhibit a broad resonance in the red part of the visible spectrum, which is qualitatively similar to localized surface plasmon (LSP) resonances in gold nanodisks. The hole resonance red-shifts with increasing hole diameter (D=60-107 nm), similar to particle LSP resonances. These features could be well reproduced by electrodynamic simulations based on the Boundary Element Method (BEM). Further, the electric field distribution around the resonant nanoholes, obtained from the BEM simulations, exhibits a clear electric dipole pattern. This confirms the assignment of the hole resonance to a dipolar LSP resonance mode. However, in comparison to Au nanodisks of similar size, the hole LSP resonance exhibits a shorter dephasing time (τ). This observation can be understood in terms of an additional decay channel that is dominated by the short wavelength anti-symmetric bound (a b) surface plasmon polariton (SPP) mode of the surrounding Au film. Experimental verification of the LSP-SPP coupling is obtained from near-field scanning optical microscopy images, which exhibit interference fringes due to SPP emission from the hole. The fringe periodicity corresponds to a SPP wavelength of λ a b ≈285 nm, much less than both the free space wavelength λ 0 =633 nm or the wavelength of the more well-known symmetric leaky mode.
Actuated Plasmonic Nanohole Arrays for Sensing and Optical Spectroscopy Applications
Nanoscale, 2020
Herein, we report a new approach to rapidly actuate the plasmonic characteristics of thin gold films perforated with nanohole arrays that are coupled with arrays of gold nanoparticles. The near-field interaction between the localized and propagating surface plasmon modes supported by the structure was actively modulated by changing the distance between the nanoholes and nanoparticles and varying the refractive index symmetry of the structure. This approach was applied by using a thin responsive hydrogel cushion, which swelled and collapsed by a temperature stimulus. The detailed experimental study of the changes and interplay of localized and propagating surface plasmons was complemented by numerical simulations. We demonstrate that the interrogation and excitation of the optical resonance to these modes allow the label-free SPR observation of the binding of biomolecules, and is applicable for in situ SERS studies of low molecular weight molecules attached in the gap between the nanoholes and nanoparticles. † Electronic supplementary information (ESI) available. See