Magnetic photonic crystals for terahertz tunable filter and multifunctional polarization controller

We numerically investigate the photonic bandgaps as well as the transmission properties of a two-dimensional magnetic photonic crystal (PC) in the terahertz (THz) region by the plane wave expansion and finite-difference time-domain methods. The calculation predicts a magnetic PC waveguide that can work as a tunable filter with a bandwidth larger than 0.1?THz, and its central frequency is from 0.83 to 1.03?THz. It also shows that a magnetic PC can be used as a polarization controller with three functions, including controllable polarizing, polarization beam splitting, and −π–π phase shifting.