On the surface plasmon polariton wave at the planar interface of a metal and a chiral sculptured thin film

Abstract

The solution of a dispersion equation indicates the theoretical existence of multiple modes of surface plasmon polariton wave propagation at the planar interface of a metal and a chiral sculptured thin film (STF). One mode appears to occur over a wide range of the structural period of the chiral STF, while all other modes exist only above some minimum value of the structural period, the minimum value being different for each mode. In order to excite the different modes, the interface can be incorporated in the commonplace Kretschmann configuration, for which our calculations show that the efficient excitation of different modes would require different numbers of structural periods of the chiral STF.

Surface plasmon resonance due to the interface of a metal and a chiral sculptured thin film

“…The experimental observation of multiple SPR therefore confirms the theoretical predictions. [6][7][8][9] Comments on the angular location and width of SPR dips are discussed by Polo and Lakhtakia. 6 These resonant phenomenon could be used for sensing purposes such as detecting biomolecules of interest for water safety.…”

“…Typically, SPPs are excited at noble metal/homogeneous dielectric material interfaces and can be observed only for the parallel polarization of the incident laser beam, p-polarization (the direction of the polarization lies in the plane of incidence). 3 Recent theoretical studies [6][7][8][9] have shown that by replacing the homogeneous dielectric material by a linear, anisotropic dielectric material, more than one SPP wave can be launched, and in the same film SPP waves can also be observed for spolarization of the incident laser beam (the direction of the polarization is perpendicular to the plane of incidence). 6,7 The theoretical basis for the excitation of multiple SPR and excitation by s-polarization is explained by Faryad and Lakhtakia.…”

“…3 Recent theoretical studies [6][7][8][9] have shown that by replacing the homogeneous dielectric material by a linear, anisotropic dielectric material, more than one SPP wave can be launched, and in the same film SPP waves can also be observed for spolarization of the incident laser beam (the direction of the polarization is perpendicular to the plane of incidence). 6,7 The theoretical basis for the excitation of multiple SPR and excitation by s-polarization is explained by Faryad and Lakhtakia. 10 Although these SPP waves propagate with the same frequency, they have different phase speeds, polariza-0091-3286/2010/$25.00 C 2010 SPIE tion states, attenuation rates, and field distributions.…”

“…11 We report the experimental observation of multiple SPR guided by a metal and a chiral sculptured thin film (metal/CSTF) interface, providing experimental confirmation of the theoretical predictions of Motyka, Polo, and Lakhtakia. [6][7][8][9] 2 Experimental Procedure To fabricate the metal/CSTF interfaces, magnesium fluoride CSTFs were deposited on borosilicate glass slides that had been previously coated with a gold film. The gold films were deposited by sputtering gold in argon plasma at 5 mTorr.…”

Commentary: Multiple surface-plasmon-polariton waves at a single bi-material interface

“…Truly surprising results were revealed when calculations [4] were directed at SPP waves bound to the interface of a metal and the more complicated chiral STF. Multiple SPP-wave modes of propagation bound to a single interface for a single frequency of excitation were found.…”