Transformation optics for plasmonics: from metasurfaces to excitonic strong coupling

Abstract

We review the latest theoretical advances in the application of the framework of Transformation Optics for the analytical description of deeply sub-wavelength electromagnetic phenomena. First, we present a general description of the technique, together with its usual exploitation for metamaterial conception and optimization in different areas of wave physics. Next, we discuss in detail the design of plasmonic metasurfaces, including the description of singular geometries which allow for broadband absorption in ultrathin platforms. Finally, we discuss the quasi-analytical treatment of plasmon-exciton strong coupling in nanocavities at the single emitter level.Résumé. Nous passons en revue les dernières avancées dans l'application du cadre de l'optique transformationnelle pour la description analytique des phénomènes électromagnétiques en régime fortement sublongueur d'onde. En premier lieu, nous présentons une description générale de la technique, ainsi que son exploitation usuelle dans la conception et l'optimisation des métamatériaux dans différentes disciplines de la physique des ondes. En second lieu, nous discutons en détail de la conception de métasurfaces plasmoniques, y compris la description de géométries singulières qui permettent une absorption sur une large plage de fréquences dans les plates-formes ultra-minces. Enfin, nous discutons du traitement quasi-analytique du couplage fort plasmon-exciton dans les nanocavités au niveau d'un seul émetteur.

A Theoretical Perspective on Molecular Polaritonics

“…In this approximation, retardation effects, and therefore EM propagation into free space (or bulk dielectric media), is neglected, resulting in purely longitudinal fields. In this limit, semianalytical solutions are often again possible, e.g., using transformation optics, − with the resulting modes being fully bound while still describing the material losses. Since subwavelength confinement is a prerequisite for the quasistatic approximation, these material losses will always be significant .…”

Transformation Metamaterials

“…Thereafter, tremendous TO devices and their metamaterial achievements were reported, like carpet cloaks, [ 41–46 ] field rotators, [ 47,48 ] field concentrators, [ 49,50 ] field shifters, [ 51,52 ] field bending, [ 53–56 ] transmutated singular devices, [ 57–60 ] and optical illusion devices. [ 61–65 ] There are lots of reviews about TO and metamaterals of EM waves [ 66–83 ] from different perspectives. Furthermore, the TO method and metamaterials were extended to diverse waves, like surface plasmonics, [ 84–87 ] acoustics, [ 88–90 ] and thermotics.…”

“…field rotators, [47,48] field concentrators, [49,50] field shifters, [51,52] field bending, [53][54][55][56] transmutated singular devices, [57][58][59][60] and optical illusion devices. [61][62][63][64][65] There are lots of reviews about TO and metamaterals of EM waves [66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83] from different perspectives. Furthermore, the TO method and metamaterials were extended to diverse waves, like surface plasmonics, [84][85][86][87] acoustics, [88][89][90] and thermotics.…”

Optimization of second-harmonic generation from touching plasmonic wires

“…In [26], we introduced an analytic tool for this class of problems, namely, transformation optics (TO). This technique rose to fame in facilitating the design of the invisibility cloaks [27], and was later used for the interpretation and design of a range of plasmonic structures [28][29][30][31]. Our implementation uses TO to study nonlinear optical wave mixing.…”