Multiple trains of same-color surface plasmon-polaritons guided by the planar interface of a metal and a sculptured nematic thin film. Part IV: Canonical problem

Abstract

The canonical problem of the propagation of surface-plasmon-polariton (SPP) waves localized to the planar interface of a metal and a sculptured nematic thin film (SNTF) that is periodically nonhomogeneous along the direction normal to the interface was formulated. Solution of the dispersion equation obtained thereby confirmed the possibility of exciting multiple SPP waves of the same frequency or color. However, these SPP waves differ in phase speed, field structure, and the e-folding distance along the direction of propagation.

Multiple trains of same-color surface plasmon-polaritons guided by the planar interface of a metal and a sculptured nematic thin film

“…Multiple SPP waves can be excited and propagate along the planar interface of a metal and a periodically nonhomogeneous dielectric material [17]. The partnering dielectric material may be a rugate filter [18], a columnar thin film, a sculptured nematic thin film [19], or a chiral sculptured thin film [20]. Error-free sensing [21], optical sensing of multi-analytes and solar-energy harvesting are possible applications of surface multiplasmonics [22].…”

“…The period has to be greater than a certain value to ensure the multiplicity and the existence of s-polarized SPP waves. However, there is a maximum period so that the dielectric is not essentially uniform [19]. The two nonhomogeneous dielectric materials to be examined in this thesis are rugate filter and sculptured nematic thin film (SNTF).…”

“…The characteristic of the structure has been implemented to design and fabricate rugate filters [24]. It has been documented that multiple SPP waves with the same frequency but different phase speed, attenuation rates, and spatial field profiles can be guided by metal/SNTF interface in the prismcoupled and grating coupled configurations [19,21,[25][26][27]. Grounded on the previous work, this thesis is devoted to the enhancement and the wide range of possibilities for the angular momentums that the availability of multiple SPPs waves may offer.…”

“…Let the SPP wave propagate in the direction of unit vector � along the interface z=0 and attenuate as → ±∞. In the region z<0, the wave vector may be written as [19] = � − � ,…”

“…is the inclination angle of the columnar morphology with respect to the same plane. These four quantities depend on ( ′ ), the conditions for the fabrication of the SNTF, and the material(s) evaporate to fabricate the SNTF [19].…”