One-dimensional Photonic Superlattices Research Articles

Controlling the null photonic gap and zero refractive index in photonic superlattices with temperature-controllable-refractive-index materials

Temperature-adjustable optical properties of two types of one-dimensional photonic superlattices made from lithium niobate or liquid crystal are theoretically investigated. The control of band structures and density of states is achieved through the temperature with various values of refractive index, layer width, and propagation wavelength. It is presented that a null photonic gap appears at certain temperature points, which are decided by the ratio of layer width and the refractive index. It is shown that the spatial average of the wave vector ⟨ k ⟩ vanishes at a specific temperature as functions of the layer thickness and refractive index. The values of the temperature corresponding to zero-refractive-index (zero- ⟨ n ⟩ ) are demonstrated to be suppressed when the refractive index or the ratio of the layer width is enhanced. Null photonic gap and zero- ⟨ n ⟩ can appear simultaneously at certain wavelengths in the range of visible light, which can be modulated by the temperature. This implies the importance of one-dimensional photonic superlattices made from temperature-controllable-refractive-index materials for many important practical applications.

Topological interface modes in photonic superlattices containing negative-index materials

We study the topological properties of one-dimensional photonic superlattices consisting of alternating layers of positive- and negative-index materials. We find that Zak phases of photonic bands of such superlattices are related to the signs of the spatial average of their permittivity and permeability, and the polarization of incident light. Specifically, the Zak phases for transverse electric (TE) waves (transverse magnetic (TM) waves) are determined by only the sign of the spatially averaged permittivity (permeability) of the lattices. Only a single-polarized (TM or TE) topological interface mode occurs at the interface between air and the superlattice with single-negative average permittivity or permeability. The crucial dependence of the topological property of the superlattice on the light polarization suggests a polarization filter application. The topologically protected interface modes for both TM and TE polarizations can coexist at the interface separating air and the superlattices with simultaneously negative signs of averaged permittivity and permeability. The robustness of such topological interface modes for both TM and TE polarizations is also demonstrated.

Bulk-like-phonon polaritons in one-dimensional photonic superlattices

We investigate the properties of a one-dimensional photonic superlattice made of alternating layers of air and wurtzite aluminum nitride. The Maxwell equations are solved for any admissible values of the angle of incidence by means of the transfer matrix formalism. The band structure of the frequency spectrum is obtained, as well as the density of states and transmittance associated to both the TM and TE modes. The dispersion relations indicate that for oblique incidence and TM modes there is a component of the electric field oriented along the growth direction of the structure that couples with the longitudinal optical phonon oscillations of the aluminum nitride thus leading to the appearance of longitudinal phonon polaritons in the system.

Zero-[formula omitted] band gap in two-dimensional metamaterial photonic crystals

We have theoretically studied metamaterial photonic crystals (PCs) composed by air and double negative (DNG) material. Numerical data were obtained by means of the finite difference time-domain (FDTD) method, with results indicating the possibility for the existence of the zero-n¯ non-Bragg gap in two-dimensional metamaterial PCs, which has been previously observed only in one-dimensional photonic superlattices. Validity of the present FDTD algorithm for the study of one-dimensional metamaterial PCs is shown by comparing with results for the transmittance spectra obtained by means of the well known transfer matrix method (TMM). In the case of two-dimensional metamaterial PCs, we have calculated the photonic band structure (PBS) in the limiting case of a one-dimensional photonic superlattice and for a nearly one-dimensional PC, showing a very similar dispersion relation. Finally, we show that due to the strong electromagnetic field localization on the constitutive rods, the zero-n¯ non-Bragg gap may only exist in two-dimensional systems under strict geometrical conditions.

Properties of plasmon-polariton modes in one-dimensional photonic superlattices made of Rudin-Shapiro bases

Theoretical investigations on the features of the plasmon-polariton frequency spectrum in one-dimensional photonic superlattices with Rudin-Shapiro dielectric layered unit cell are preformed. The plasmon polariton dispersion relations as well as the dependence on the angle of incidence of the Bragg and plasmon-polariton photonic bandgaps are reported. Results show that plasmon-polariton modes are robust even in the presence of rather large absorption. The outcome of the study shows that the reduced plasmon-polariton dispersion relation obtained within a Drude-like dielectric model points at a multifractal character under lossless conditions.

Omnidirectional suppression of Anderson localization of light in disordered one-dimensional photonic superlattices

The omnidirectional suppression of Anderson localization of light in a disordered one-dimensional normal-metamaterial photonic superlattice is thoroughly investigated. Analytical conditions relating to the electric-permittivity and magnetic-permeability responses of each slab of the heterostructure are established for the omnidirectional divergence of the localization length of the normal-metamaterial superlattice. The robustness of such conditions with respect to the degree of disorder of the superlattice is also analyzed.

Bulk-plasmon polaritons in metamaterial–metamaterial one-dimensional photonic superlattices

We perform a theoretical study of the bulk-plasmon polaritons in one-dimensional photonic superlattices made up of alternate layers of different metamaterials with dispersive dielectric permittivities and magnetic permeabilities for both normal and oblique incidence. We demonstrate that for oblique incidence a finite projection along the growth direction of the electric or magnetic field of the incident wave associated with the transverse-magnetic or transverse-electric modes, respectively, leads to a coupling in each layer of the heterostructure of the photon modes with the bulk electric or magnetic metamaterial plasmons, respectively. Such photon-plasmon coupling gives rise to electric or magnetic longitudinal bulk-plasmon polariton bands in the photonic band structure of the metamaterial–metamaterial superlattice. We also analyze the conditions for suppression of the longitudinal bulk-plasmon polaritons in the photonic band structure and reflection spectra of such metamaterial–metamaterial heterostructures.

Hydrostatic Pressure and Temperature Dependence of the Band Structure in a 1-D Semiconductor Phtonic Crystal

The band structure of a one-dimensional photonic superlattice composed of alternate layers of air and GaAs characterized by different refractive indexes have been theoretically investigated using a transfer matrix technique. In addition to the well known existence of the band gaps, we show that the band gaps depends on the width relationship between the layers materials, also, we have found that the temperature dependence of the photonic band structure is negligible, however its main changes are due to the variations of the width and the dielectric constant of the layers of GaAs, caused by the applied hydrostatic pressure.

Plasmon polariton and〈n〉=0non-Bragg gaps in superlattices with metamaterials

We consider one-dimensional photonic superlattices made up of alternate layers of a right-handed nondispersive material and a metamaterial with Drude-type dielectric permittivity and magnetic permeability. By thoroughly investigating the dispersion relation for the propagation of obliquely incident optical fields obtained from Maxwell's equations and the transfer-matrix technique, we demonstrate that, in the long-wavelength limit, the dispersion is the same that one would obtain by considering a homogeneous effective medium with Drude-type responses at shifted electric and magnetic plasmon frequencies. Moreover, we show that the plasmon polariton and $\ensuremath{\langle}n\ensuremath{\rangle}=0$ non-Bragg gaps correspond to regions of the low-energy spectrum where the effective medium is absorptive, exhibiting an imaginary effective refraction index.

Surface superlattice solitons in nonlocal nonlinear media

We analyse surface solitons at the interface between a one-dimensional photonic superlattice and a uniform medium with weak nonlocal nonlinearity. We demonstrate that in deep lattices there exist three kinds of surface solitons when the propagation constant exceeds a critical value, including two on-site solitons and one off-site soliton. These three kinds of surface solitons have unique dynamical properties. If the relative depth of the superlattice is low, there is only one kind of off-site soliton; however, the solitons of this kind can propagate stably, unlike their deep superlattice counterparts. Dipole surface solitons are also investigated, and the stable domain is given.

Surface superlattice gap solitons

We demonstrate that specific surface superlattice gap solitons can be supported at an interface between a one-dimensional photonic superlattice and a uniform medium with saturable nonlinearity. The solitons are stable in the semi-infinite gap but do not exist in the first gap. With the decrease of the power, the solitons jump from the surface site to the next one, and they may continue the motion into the lattices, which offers potential applications for the routing of optical signals.

Band structure and band-gap control in photonic superlattices

The photonic band structure as well as the density of photon states of a one-dimensional photonic superlattice comprised of alternate layers of air and $\mathrm{GaAs}$ are theoretically investigated within the transfer-matrix formalism. The existence of photonic superlattices of null gap with band-touching phenomena is demonstrated, indicating the importance of one-dimensional photonic superlattices for many important practical applications.