Self-collimated beams in two-dimensional photonic crystals: Properties and applications

The propagation properties of a self-collimated beam in two-dimensional photonic crystals have been investigated by using equifrequency contour calculations and finite-difference time-domain simulations. Total internal reflection of self-collimated beams can occur at the interfaces of photonic crystals and air. The Goos-Hanchen shift of self-collimated beams totally reflected at the photonic crystal-air interface can be much smaller than the wavelength of the incident beam. We have also showed that a line defect can reflect self-collimated beams; thus, the power of self-collimated beam can be split by a line defect. The power ratio between two split self collimated beams can be controlled by varying the radii of the rods in the line defect. The controllable splitting of self-collimated beams can be useful in steering the flow of light in photonic crystals.