Dispersion engineering with plasmonic nano structures for enhanced surface plasmon resonance sensing

Abstract

We demonstrate numerically and experimentally the enhancement of Surface Plasmon Resonance (SPR) sensing via dispersion engineering of the plasmonic response using plasmonic nanograting. Following their design and optimization, the plasmonic nanograting structures are fabricated using e-beam lithography and lift-off process and integrated into conventional prism based Kretschmann configuration. The presence of absorptive nanograting near the metal film, provides strong field enhancement with localization and allows to control the dispersion relation which was originally dictated by a conventional SPR structure. This contributes to the enhancement in Q factor which is found to be 3–4 times higher as compared to the conventional Kretschmann configuration. The influence of the incident angle on resonance wavelength is also demonstrated both numerically and experimentally, where, only a negligible wavelength shift is observed with increasing the incident angles for plasmonic nanograting configuration. This surprising feature may be helpful for studying and utilizing light-matter interaction between plasmons and narrow linewidth media (e.g. Rb atom or molecule) having nonlocalities in their susceptibility-momentum relation. Finally, we analyze the role of plasmonic nanograting in enhancing the performance of an SPR sensor. Our results indicate that the integrated SPR-nanograting device shows a great promise as a sensor for various types of analytes.

First Principles Calculation of Optical Properties of Transition Metals for Surface Plasmon Resonance Application

“…The contribution of the intraband transition gives a tail effect on the calculation results for low energy. At 0−6 eV, the peaks of the spectrum in the optical conductivity are [34], Ag [35], and Au [36].…”

Relation between Resonance Parameters of Surface Plasmon-Polariton Waves with Properties of the Dielectric-Metal Film-Dielectric Waveguide

“…One of the two propagation constants β under resonance is real according to [9,18]. Thus, the following relation is true:…”

“…It should be noted, that it is possible to increase the accuracy of detecting the values of the angles or wavelengths at which the reflectance minima are observed. In [9], it is proposed to cover a gold film with the gold grating with a period several times smaller than the wavelength. This contributed to the enhancement in the Q factor which was found to be 3-4 times higher as compared to the conventional Kretschmann configuration.…”

Abrupt phase change in graphene-gold spr-based biosensor

“…Surface plasmons (SPs) are collective oscillations of free electrons at the metal-dielectric interface [5]. Coupling of the incident light with SPs leads to the formation of a Surface plasmon polariton (SPPs), which propagate along the metal-dielectric interface and decays exponentially in a direction perpendicular to the interface [6,7].…”