Liquid-crystal-filled photonic crystal for terahertz switch and filter

The effects of magnetic birefringence of liquid crystal E7 on the photonic bandgaps and the transmitting properties in two-dimensional photonic crystal waveguides are investigated by using the plane wave expansion and finite-difference time domain methods. Detailed calculations on the shifts and variations in the frequency width of bandgaps reveal that under the control of an external magnetic field the two-dimensional liquid-crystal-filled photonic crystal waveguide can serve as a switch and continuously tunable bandpass filter at the terahertz wave band. (c) 2008 Optical Society of America