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We analyze self-collimation in two-dimensional periodic complex lattices. We consider P-symmetric and PT-symmetric complex lattices with different geometries, where the periodic modulations of both refractive index and gain-loss are either in-phase, or dephased a quarter of wavelength of the modulation. The non-diffractive propagation of light beams is analytically predicted using coupled mode approach...
We propose for the first time a simple realization of a two-dimensional Parity-Time symmetric hexagonal shaped photonic structure composed of honeycomb lattice. The structure has a symmetric periodic modulation of the refractive index on the wavelength scale, which is combined with an anti-symmetric gain/loss distribution on the same scale. That leads to non-reciprocal light coupling at resonant frequencies...
We propose a simple realization of a 2-dimensonal (2D) PT-symmetric photonic structure: a honeycomb arrangement of alternating cylinders with gain or loss in a dielectric background. The structure provides a periodic modulation of the refractive index on the wavelength scale, which combined with an anti-symmetric gain/loss distribution on the same scale, leads to non-reciprocal light coupling at resonance...
We predict and show the existence of unlocked evanescent waves in two dimensional periodic structures. In a one dimensional periodic structure an evanescent mode are located either at the center or at the boundary of the Brillouin Zone, and the real part of wave-vectors is locked either to zero or to the modulation vector of the periodicity. However, we report an unexpected observation that this is...
The propagation of light through materials with periodically modulated gain can present different effects that are analyzed in the paper. The characterization of these gain/loss metamaterials (GLM) with a two-dimensional modulation predicts the mode locked states and effects like non diffractive propagation of beams, superluminar light propagation regimes and superdiffusion due to angular gain dependence...
We are making a study of the out-of-plane losses for the second harmonic generation process in planar two-dimensional photonic crystals made from Al0.3Ga0.7As. We found that for the rhombic symmetry of the lattice it can be obtained a structure in which the out-of-plane losses vanish for both fundamental and second harmonic waves in conditions of very small diffraction for the second harmonic wave...
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