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Optical nonreciprocal transmission possesses a broad range of applications such as optical isolation, all-optical signal processing, and integrated photonic circuits. The main underlying mechanism is that a static magnetic field can break the time-reversal symmetry in the presence of magneto-optical materials. However, the typical devices usually need a large size because the magneto-optical activity of materials is weak. In this paper, we realize strong nonreciprocal transmission in a one-dimensional photonic crystal with a magnetized epsilon-near-zero defect. The inherent weak magneto-optical activity is significantly enhanced in the magnetized epsilon-near-zero defect because of the field intensity enhancement mechanism. Our results show that the wavelength shift of transmission peaks along two opposite incident directions can be up to 100 times higher than that in the case of a bismuth-iron-garnet defect. These results provide a new perspective to design novel magneto-optical devices with a small size and open novel routes to exploit advanced materials for steering the electromagnetic waves in nano-scale structures. [ABSTRACT FROM AUTHOR]

Photonic gaps are the core of photonic crystals in the manipulation of light. However, in conventional photonic crystals composed of two types of dielectrics, the photonic gaps strongly depend on the angle of incidence, which limits their applications. In this Letter, we present the experimental demonstration of angle-independent gaps in the visible wavelength range in onedimensional photonic crystals composed of layered hyperbolic metamaterials (HMMs) and dielectrics. HMMs with anomalous wave-vector dispersion can tune the propagating phase of light to an unprecedented extent that usual dielectrics cannot attain. The HMM is mimicked by the layered titanium dioxide and silver with a subwavelength unit cell. Based on the phase-variation compensation effect between the HMM and the dielectric, an angle-independent gap is experimentally realized, which agrees well with the simulated one. This angle-independent gap is very useful in the design of photonic devices such as omnidirectional reflectors with fixed bandwidth or all-angle filters. [ABSTRACT FROM AUTHOR]

Optical Tamm states (OTSs) in hetero-structures consisting of highly dispersive planar plasmonic metamaterials and truncated photonic crystal (PC) are investigated numerically. Compared to conventional OTSs in metal-PC structures, the reflectance of tunneling mode can be reduced from -10.2 dB to -32.0 dB, with an optimized Q-factor up to 17 times higher simultaneously. Further study on electromagnetic (EM) field distribution confirms that EM waves are highly localized at some special points. The confinement along the propagating direction provided by OTSs and the in-plane localization originated from the planar plasmonic metamaterials give rise to the three-dimensional enhancement of sub-wavelength EM localization corporately. As the advantages above are not at a cost of extra device volume, this structure is promising to be applied in highly sensitive dielectric sensing, nonlinear optical devices, and so on. [ABSTRACT FROM AUTHOR]