Tunable negative refraction properties of photonic crystals based on silicon columns arranged in magnetic liquids

Abstract

Tunable negative refraction of two-dimensional photonic crystal made of silicon cylinders hexagonally arranged in a MnFe2O4 magnetic liquid is studied. The plane wave expansion and finite-difference time-domain method are used to calculate and simulate its band structure, equi-frequency surface and negative refraction property. For the TE mode, the negative refraction of the two-dimensional photonic crystal made of the silicon column-magnetic liquid system can be tuned by a magnetic field. When the volume fraction of magnetic nanoparticles within the magnetic liquid and the frequency of the incident light are fixed, the deflection angle of the refraction light and the absolute value of the negative refractive index increase gradually with the external magnetic field increasing. When the volume fraction of magnetic nanoparticles within the magnetic liquid and the strength of the external magnetic field are fixed, the absolute value of the negative refractive angle and negative refractive index decrease with the normalized frequency of the incident light increasing. In addition, when the external magnetic field and the normalized frequency of the incident light are fixed, the negative refraction weakens with the increase of magnetic nanoparticle volume fraction of background solution.