A Tunable Terahertz Photonic Crystal Narrow-Band Filter

We theoretically propose and investigate a magnetically tunable narrow-band terahertz filter based on a triangular lattice silicon photonic crystal with a point and two line defects. The optical properties of the filter have been analyzed in detail. It is found that a single resonant peak with the central frequency of <tex-math notation="LaTeX">~ 1 </tex-math> THz is existed in the transmission spectrum, which has a narrow full width at half maximum of <2 GHz. Moreover, under the control of an external magnetic field, transmission frequency and width of passband are adjustable, which reveals that the 2-D silicon photonic crystal waveguide with point and line defects can serve as a continuously tunable bandpass filter at the terahertz waveband.