35 research outputs found
Localized modes in chiral photonic structures
No full textТекст статьи не публикуется в открытом доступе в соответствии с политикой журнала.We discuss chiral structures in self-organizing, artificial, and biological materials. A review of experimental studies and recent advances in the localization of light in chiral structures is given. The behavior of polarized resonant modes in such structures is examined using the example of a one-dimensional photonic crystal containing liquid crystal materials. The anomalous spectral shifts of transmission peaks are interpreted as the contribution of the geometric phase caused by the twisting of the layers of the liquid crystal. The optical Tamm state localized at the boundary between chiral and nonchiral mirrors in the form of a cholesteric layer and a polarization-preserving anisotropic mirror is analytically and numerically described. Considerable attention is paid to the presentation of the properties of localized optical modes in the cholesteric with a resonant metal-dielectric nanocomposite. New possibilities for controlling the properties of the photonic structure are noted, due to the combination of the dispersion of the resonant medium and the intrinsic dispersion of the cholesteric. Attention is focused on controlled hybrid modes in the cholesteric structure formed by the coupling of localized modes. Possible applications and further ways of developing the concept of chiral photonic structures are deliberated
Epsilon-Near-Zero Absorber by Tamm Plasmon Polariton
No full textTwo schemes of excitation of a Tamm plasmon polariton localized at the interface between a photonic crystal and a nanocomposite with near-zero effective permittivity have been investigated in the framework of the temporal coupled-mode theory. The parameters of the structure have been determined, which correspond to the critical coupling of the incident field with a Tamm plasmon polariton and, consequently, ensure the total absorption of the incident radiation by the structure. It has been established that the spectral width of the absorption line depends on the scheme of Tamm plasmon polariton excitation and the parameters of a nanocomposite film. The features of field localization at the Tamm plasmon polariton frequency for different excitation schemes have been examined. It has been demonstrated that such media can be used as narrowband absorbers based on Tamm plasmon polaritons localized at the interface between a photonic crystal and a nanocomposite with near-zero effective permittivity
Two Types of Localized States in a Photonic Crystal Bounded by an Epsilon near Zero Nanocomposite
No full textThe spectral properties of a one-dimensional photonic crystal bounded by a resonant absorbing nanocomposite layer with the near-zero permittivity have been studied. The problem of calculating the transmittance, reflectance, and absorptance spectra of such structures at the normal and oblique incidence of light has been solved. It is shown that, depending on the permittivity sign near zero, the nanocomposite is characterized by either metallic or dielectric properties. The possibility of simultaneous formation of the Tamm plasmon polariton at the photonic crystal/metallic nanocomposite interface and the localized state similar to the defect mode with the field intensity maximum inside the dielectric nanocomposite layer is demonstrated. Specific features of field localization at the Tamm plasmon polariton and defect mode frequencies are analyzed
Two Types of Localized States in a Photonic Crystal Bounded by an Epsilon near Zero Nanocomposite
No full textThe spectral properties of a one-dimensional photonic crystal bounded by a resonant absorbing nanocomposite layer with the near-zero permittivity have been studied. The problem of calculating the transmittance, reflectance, and absorptance spectra of such structures at the normal and oblique incidence of light has been solved. It is shown that, depending on the permittivity sign near zero, the nanocomposite is characterized by either metallic or dielectric properties. The possibility of simultaneous formation of the Tamm plasmon polariton at the photonic crystal/metallic nanocomposite interface and the localized state similar to the defect mode with the field intensity maximum inside the dielectric nanocomposite layer is demonstrated. Specific features of field localization at the Tamm plasmon polariton and defect mode frequencies are analyzed
Transparent conductive oxides for the epsilon-near-zero Tamm plasmon polaritons
No full textWe demonstrate the possibility of using transparent conducting oxides [aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium tin oxide (ITO)] to form Tamm plasmon polaritons in the near-infrared spectral range where the permittivity of oxides is near zero. The spectral properties of the structures are investigated in the framework of the temporal coupled-mode theory and confirmed by the transfer matrix method. It is found that in the critical coupling conditions, the maximal -factor of a Tamm plasmon polariton is achieved when a photonic crystal is conjugated with the AZO film, while at the conjugation with the ITO films, the broadest spectral line is obtained. The sensitivity of the wavelength and spectral width of the Tamm plasmon polariton to changes in the oxide film thickness, bulk concentration of a dopant, and angle of incidence is demonstrated
Tunable hybrid optical modes in a bounded cholesteric liquid crystal with a twist defect
No full textCoupling between the defect mode of a cholesteric liquid crystal and the localized mode of a cholesteric liquid crystal–phase plate–metal structure is theoretically demonstrated. It is shown that the transmittance spectrum can be tuned by changing the twist-defect angle and helix pitch, which are governed by external factors. The spectra for different circular polarizations of the incident light are different; specifically, at the nondiffracting polarization, there is no defect-mode transmittance peak
Hybrid Tamm and surface plasmon polaritons in resonant photonic structure
No full textHybrid modes originating from the coupling of the Tamm and surface plasmon polaritons excited in a one-dimensional resonant photonic structure are demonstrated. The structure represents a photonic crystal bounded by a nanocomposite film consisting of a transparent matrix and silver nanoparticles uniformly distributed over its volume. In comparison with structures on planar metal films the volume concentration and shape of nanoparticles are of great help in configuring the hybrid mode properties, including their wavelength and splitting. Also the radiation incidence angle variation opens the possibility of fine-tuning the energy spectra of the structure. We demonstrate the high-sensitivity of optical sensors based on the resonant photonic structure
Tunable hybrid Tamm-microcavity states
No full textSpectral manifestations of hybrid Tamm-microcavity modes in a 1D photonic crystal bounded with a silver layer and containing a nematic liquid crystal microcavity layer have been studied using numerical simulation. It is demonstrated that the hybrid modes can be effectively tuned owing to the high sensitivity of the liquid crystal to the temperature and external electric field variations. It is established that the effect of temperature on the transmission spectrum of the investigated structure is most pronounced at the point of the phase transition of the liquid crystal to the isotropic state, where the refractive index jump is observed
