Sensitivity comparison of localized plasmon resonance structures and prism coupler

Abstract

a b s t r a c tPlasmon resonances are widely used in biomolecular sensing and continue to be an active research field due to the rich variety of surface and measurement configurations, some of which exhibit down to single molecule level sensitivity. The resonance wavelength shift of the plasmonic structure upon binding of molecules, strongly depends, among other parameters, on how well the field of the resonant mode is confined to the binding site. Here it is shown that, by using properly designed metal-insulatormetal type resonators, improved wavelength response can be achieved with localized surface plasmon resonators (LSPRs) compared to that of the commonly used Kretschmann geometry. Using computational tools we investigate theoretically the refractive index response of several LSPR structures to a 2 nm thin film of binding molecules. LSPR resonators are shown to feature improved sensitivity over conventional Kretschmann geometry in the wavelength interrogation scheme for such a thin film. Moreover, some of the LSPR modes are quasi-omnidirectional and such angular independence (up to 30 • angle of incidence) allows higher numerical apertures to be used in colorimetric imaging. Results highlight the potential of LSPRs for biomolecular sensing with high sensitivity and high spatial resolution.

Reticular plasmon resonance detection properties of metal nanoparticles

“…3 presents a comparison of the field properties simulations in two cases of normal and oblique incidence. The structure is expected to change the sensitivity of the refractive index from the lower to the outside, since the confined field around nanoparticle [5,54].…”

“…We can expect that the structure having an exposed surface of the graphene layer has an improved sensitivity and FoM to the variation of the angle of incidence. To understand these trends in detail, we will focus on the variations of geometric parameters of the bi-dimensional nanostructures of nanoparticles of gold form (T), which shows the plasmon resonances of network surface [54]. Fig.…”

Effect of graphene layer on the localized surface plasmon resonance (LSPR) and the sensitivity in periodic nanostructure

“…The variation of the position of λ max , shows a linear dependence in accordance with the refractive index of the surrounding medium. Sensitivity, defined as the ratio of the variation of the Plasmon's position band in the variation of the refractive index [28,37].…”

Biosensors for Early Disease Diagnosis

“…A variant technique of SPR, called localized SPR (LSPR), uses metal nanoparticles (usually gold or silver) of specific sizes and geometries to further improve the detection limits of this technique (Swierczewska et al, 2012). LSPR nanostructures may be employed for biomolecule detection through the measurement of refractive index changes and colorimetric SPR imaging, and it has been shown in a theoretical study that the detection capacity of LSPRbased methods can exceed that of systems based on traditional Kretschmann geometry systems in terms of wavelength shift sensitivity outperforming the detection system with Kretschmann geometry (Kaya et al, 2014). LSPRbased detection of colon cancer was also achieved using Au nanorods, and the width-and length-dependent changes in the plasmonic and photonic prop erties of nanorod antennae were investigated to identify optimal geometries for nanorod arrays for use in cancer biosensors (Dodson et al, 2015).…”