Optical sensing of analytes in aqueous solutions with a multiple surface-plasmon-polariton-wave platform

Abstract

The commonly used optical sensor based on surface plasmon-polariton wave phenomenon can sense just one chemical, because only one SPP wave can be guided by the interface of a metal and a dielectric material contained in the sensor. Multiple analytes could be detected and/or the sensing reliability for a single analyte could be enhanced, if multiple SPP-wave modes could be excited on a single metal/dielectric interface. For that to happen, the partnering dielectric material must be periodically non-homogeneous. Using a chiral sculptured thin film (CSTF) as that material in a SPP-wave platform, we show that the angular locations of multiple SPP-wave modes shift when the void regions of the CSTF are infiltrated with a fluid. The sensitivities realized in the proof-of-concept experiments are comparable to state-of-research values.

λ3/20000 plasmonic nanocavities with multispectral ultra-narrowband absorption for high-quality sensing

“…4 Recently, enhanced plasmon resonance sensors with narrower resonant bandwidths have been reported for hybrid metallodielectric Fabry-P erot (FP) microcavities 16,17 and plasmon-waveguide systems. [18][19][20] Based on propagating surface plasmons with a narrow bandwidth of the resonance excited by a plasmonic grating array, a change in the refractive index (RI) of the metal surface superstrates could result in a modification of the propagating surface plasmon polariton spectrum. 21 Recently, with the great efforts made by the group of Bartoli et al, 22,23 high-quality biosensors with figures of merit (FOM) reaching 200 have been achieved via the interference of propagating plasmon waves in plasmonic interferometric structures.…”

Observation of the Dyakonov-Tamm Wave

“…Such changes alter the field distribution, the phase speed, and the attenuation rate of the surface wave and may even cause the surface wave to disappear entirely. This sensitivity is most often exploited for optical sensing applications [4,7,5,6], but surface waves also show potential for applications in microscopy, photovoltaics, and communication [8,9,10].Most of these applications have been realized for surface-plasmon-polariton (SPP) waves, which requires one of the two partnering materials to be a metal whereas the other one is a dielectric material. The concept of these surface waves excited at optical frequencies arose in 1957, when Ritchie [11] presented a plasma-oscillation explanation for energy losses of fast electrons traversing thin metal films.…”

Surface multiplasmonics for optical sensing

“…On one face of each substrate, a 30-nm-thick aluminum thin film was deposited first, followed by either a two-or three-period-thick chiral STF of lanthanum fluoride of pitch 2Ω = 400 nm. 28 The other face of the substrate was then affixed to the hypotenuse of the prism using an index-matching liquid. The sample-prism combination was then mounted on a custom-built machine that measures R as a function of φ.…”