scholarly journals Simulation of Surface Plasmon Resonance (SPR) of Silver with Titanium Oxide as a Bi-Layer Biosensor

Author(s):  
Farah Kadhum ◽  
Shaymaa Kafi ◽  
Asrar Saeed ◽  
Ali Al-Zuky ◽  
Anwar Al-Saleh

Surface plasmon resonance (SPR) is a highly sensitive method for monitoring changes in the optical characteristics that are near the sensor surface. It can be stimulated by an evanescent field that comes from the total internal reflection of the backside of the sensor surface in the Otto setup. In this setup, SPR can be used to build a simulation model at different thicknesses of titanium oxide (TiO2) (dTiO2 = 50 nm) and silver (Ag) (dAg = 10–80 nm) layers, which are deposited on the semicircular glass prism D-ZLAF50 by using water as a sensing medium. The surface plasmon resonance angle (θSPR) properties were calculated; SPR was not observed in the ultraviolet region (300 nm) or in the infrared region at 800 nm, but appeared strongly in the visible region at 600 and 700 nm and in the infrared region (900 and 1000 nm). The best sensitivity (S = 140) can be observed in the visible region, where the values of SPR dip length (Ld) and full-width half maximum (FWHM) are very good at silver layer thicknesses 40–60 nm; therefore, the proposed sensor can be used in the visible and infrared regions at the wavelengths 600, 700, 900, and 1000 nm.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kohei Shimanoe ◽  
Soshi Endo ◽  
Tetsuya Matsuyama ◽  
Kenji Wada ◽  
Koichi Okamoto

AbstractLocalized surface plasmon resonance (LSPR) was performed in the deep ultraviolet (UVC) region with Al nanohemisphere structures fabricated by means of a simple method using a combination of vapor deposition, sputtering, and thermal annealing without top-down nanofabrication technology such as electron beam lithography. The LSPR in the UV region was obtained and tuned by the initial metal film thickness, annealing temperature, and dielectric spacer layer thickness. Moreover, we achieved a flexible tuning of the LSPR in a much deeper UVC region below 200 nm using a nanohemisphere on a mirror (NHoM) structure. NHoM is a structure in which a metal nanohemisphere is formed on a metal substrate that is interposed with an Al2O3 thin film layer. In the experimental validation, Al and Ga were used for the metal hemispheres. The LSPR spectrum of the NHoM structures was split into two peaks, and the peak intensities were enhanced and sharpened. The shorter branch of the LSPR peak appeared in the UVC region below 200 nm. Both the peak intensities and linewidth were flexibly tuned by the spacer thickness. This structure can contribute to new developments in the field of deep UV plasmonics.


2004 ◽  
Vol 100 (3) ◽  
pp. 450-454 ◽  
Author(s):  
D SHANKARAN ◽  
K GOBI ◽  
K MATSUMOTO ◽  
T IMATO ◽  
K TOKO ◽  
...  

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5119 ◽  
Author(s):  
Michal Gryga ◽  
Dalibor Ciprian ◽  
Petr Hlubina

We report on a highly sensitive measurement of the relative humidity (RH) of moist air using both the surface plasmon resonance (SPR) and Bloch surface wave resonance (BSWR). Both resonances are resolved in the Kretschmann configuration when the wavelength interrogation method is utilized. The SPR is revealed for a multilayer plasmonic structure of SF10/Cr/Au, while the BSWR is resolved for a multilayer dielectric structure (MDS) comprising four bilayers of TiO2/SiO2 with a rough termination layer of TiO2. The SPR effect is manifested by a dip in the reflectance of a p-polarized wave, and a shift of the dip with the change in the RH, or equivalently with the change in the refractive index of moist air is revealed, giving a sensitivity in a range of 0.042–0.072 nm/%RH. The BSWR effect is manifested by a dip in the reflectance of the spectral interference of s- and p-polarized waves, which represents an effective approach in resolving the resonance with maximum depth. For the MDS under study, the BSWRs were resolved within two band gaps, and for moist air we obtained sensitivities of 0.021–0.038 nm/%RH and 0.046–0.065 nm/%RH, respectively. We also revealed that the SPR based RH measurement is with the figure of merit (FOM) up to 4.7 × 10−4 %RH−1, while BSWR based measurements have FOMs as high as 3.0 × 10−3 %RH−1 and 1.1 × 10−3 %RH−1, respectively. The obtained spectral interferometry based results demonstrate that the BSWR based sensor employing the available MDS has a similar sensitivity as the SPR based sensor, but outperforms it in the FOM. BSW based sensors employing dielectrics thus represent an effective alternative with a number of advantages, including better mechanical and chemical stability than metal films used in SPR sensing.


2008 ◽  
Vol 6 (5) ◽  
pp. 323-326 ◽  
Author(s):  
吴斌 吴斌 ◽  
Bin Wu Bin Wu ◽  
王庆康 王庆康 ◽  
Qingkang Wang Qingkang Wang

Author(s):  
Wei Liu ◽  
Chunjie Hu ◽  
Lei Zhou ◽  
Zao Yi ◽  
Ying Shi ◽  
...  

A highly sensitive surface plasmon resonance (SPR) sensor composed of a photonic crystal fiber (PCF) with the D-type structure is designed and analyzed by the full-vector finite element method (FEM). Indium tin oxide (ITO) is adopted as the plasmonic substance on account of the low cost and controllable infrared range (1500–2600 nm). By optimizing the structural parameters, the sensor shows a maximum wavelength sensitivity of 46,000 nm/RIU and average sensitivity of 13,166.67 nm/RIU for analyte refractive indexes between 1.355 and 1.385. This PCF combining a circular layout and D-type structure offers excellent sensitivity while the deposition and manufacturing complexity can be reduced. This sensor will possess an extremely expansive development space in the field of chemical analysis and environmental safety.


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