Theoretical Research on Tunable Slow Light Property of a Novel Magnetic Fluid Photonic Crystal

Magnetic nanoparticles in magnetic fluid film can be agglomerated to form a new type of magnetic fluid photonic crystal when magnetic field is applied perpendicular to the surface of the film. The lattice constant of the magnetic fluid photonic crystal can be tuned by changing the intensity of the applied magnetic field. In this paper, photonic bandgap of the magnetic fluid photonic crystal was analyzed theoretically, and it exhibited better magnetic tunability when the sweep rate of applied magnetic field was 2 Oe/s. Then, a magnetic fluid photonic crystal waveguide was presented, and slow light was generated. The effect of the applied magnetic field on slow light was studied based on experimental data. The results showed that group velocity below 0.35c could be obtained, and the shift of working wavelength with magnetic field intensity was the most obvious when the sweep rate of applied magnetic field was 10 Oe/s. Compared with traditional photonic crystals, the magnetic fluid photonic crystal exhibited the advantage of better magnetic tunability and easier formation, it would be potentially applied to the fabrication of new optoelectronic device.