Chiral Optical Tamm States: Temporal Coupled-Mode Theory
arXiv:1703.00310 · doi:10.3390/cryst7040113
Abstract
The chiral optical Tamm state (COTS) is a special localized state at the interface of a handedness-preserving mirror and a structurally chiral medium such as a cholesteric liquid crystal or a chiral sculptured thin film. The spectral behavior of COTS, observed as reflection resonances, is described by the temporal coupled-mode theory. Mode coupling is different for two circular light polarizations because COTS has a helix structure replicating that of the cholesteric. The mode coupling for co-handed circularly polarized light exponentially attenuates with the cholesteric layer thickness since the COTS frequency falls into the stop band. Cross-handed circularly polarized light freely goes through the cholesteric layer and can excite COTS when reflected from the handedness-preserving mirror. The coupling in this case is proportional to anisotropy of the cholesteric and theoretically it is only anisotropy of magnetic permittivity that can ultimately cancel this coupling. These two couplings being equal results in a polarization crossover (the Kopp--Genack effect) for which a linear polarization is optimal to excite COTS. The corresponding cholesteric thickness and scattering matrix for COTS are generally described by simple expressions.
the text is available both in English and in Russian, reported at ACLC-2017 (http://aclc2017.conf.tw/)
References in corpus (7)
- Electrically tunable selective reflection of light from ultraviolet to visible and infrared by heliconical cholesterics
- Unusual Resonators: Plasmonics, Metamaterials, and Random Media
- Critical coupling to Tamm plasmons
- Chiral optical Tamm states at the boundary of the medium with helical symmetry of the dielectric tensor [In Russian]
- Modulation of unpolarized light in planar aligned subwavelength-pitch deformed-helix ferroelectric liquid crystals
- Remarkable optics of short-pitch deformed helix ferroelectric liquid crystals: symmetries, exceptional points and polarization-resolved angular patterns
- Spectral and polarization properties of 'cholesteric liquid crystal - phase plate - metal' structure