Transmission characteristics of linearly polarized light in reflection-type one-dimensional magnetophotonic crystals

The propagation properties of linearly polarized light in reflection・type one-dimensional magnetoph tonic crystals are studied by using the 4×4 transmission matrix method.The structure models of reflectiotype one-dimensional magnetophotonic crystals are designed,the magnetic field direction control characteristics of reflection spectrum and Kerr rotation angle are discussed,and the effect of applied magnetic field direction and strength on reflection spectrum and Kerr rotation angle are analyzed.The results show that the non-diagonal elements in the dielectric constant of magneto optical materials change when the angle φ between applied magnetic field and optical path changes,the reflectivity and Kerr rotation angle decrease when the angle φ increases;when the applied magnetic field strength changes,the reflectivity and Kerr rotation angle increase when the applied magnetic field strength increases;by adjusting the angleφ and strength of the applied magnetic field,the rotation angle of Kerr can be adjusted to 45°,and a more flat reflection spectrum can be obtained by designing the appropriate structure.

Giant enhancement of Kerr rotation in two-dimensional Bismuth iron garnet/Ag photonic crystals

Kerr effects of two-dimensional （2D） Bismuth iron garnet （BIG）/Ag photonic crystals （PCs） combined magnetic and plasmonic functionalities is investigated with the effective medium theory. An analytical expression of Kerr rotation angles is derived, in which the effects of the surface pasmons polaritons （SPP） on magneto--optical （MO） activities are reflected. The largest enhancement of Kerr rotation up to now is demonstrated, which is improved three orders of magnitude compared with that of BIG film. When λ 〈 750 nm all of the reflection are over 10% for the arbitrary filling ratio fl, in addition, the enhancement of Kerr rotation angles are at least one order of magnitude.

Defect-mode and Fabry-Perot resonance induced multi-band nonreciprocal thermal radiation

According to Kirchhoff's radiation law,the spectral-directional absorptivity(α)and spectral-directional emissivity(e)of an object are widely believed to be identical,which places a fundamental limit on photonic energy conversion and management.The introduction of Weyl semimetals and magneto-optical(MO)materials into photonic crystals makes it possible to violate Kirchhoff's law,but most existing work only report the unequal absorptivity and emissivity spectra in a single band,which cannot meet the requirements of most practical applications.Here,we introduce a defect layer into the structure composed of one-dimensional(1D)magnetophotonic crystal and a metal layer,which realizes dual-band nonreciprocal thermal radiation under a 3-T magnetic field with an incident angle of 60°.The realization of dual-band nonreciprocal radiation is mainly due to the Fabry-Perot(FP)resonance occurring in the defect layer and the excitation of Tamm plasmon,which is proved by calculating the magnetic field distribution.In addition,the effects of incident angle and structural parameters on nonreciprocity are also studied.What is more,the number of nonreciprocal bands could be further increased by tuning the defect layer thickness.When the defect layer thickness increases to 18.2μm,tri-band nonreciprocal thermal radiation is realized due to the enhanced number of defect modes in the photonic band gap and the FP resonance occurring in the defect layer.Finally,the effect of defect location on nonreciprocity is also discussed.The present work provides a new way for the design of multi-band or even broad-band nonreciprocal thermal emitters.