Bandgap properties of diamond structure photonic crystals with line defects

Three dimensional diamond structure photonic crystals with line defects fabricated by rapid prototyping and gel casting with alumina were studied. The influence of the line defect shapes, which include rectangular, ellipse, circle, and square shapes of the cross section, on the transmission properties of the electromagnetic wave was first studied. The resonant mode of the rectangular line defect is the strongest with the guiding band from 11.0 to 11.75GHz and the normalized resonant intensity is 0.8. If the TE10 mode of the propagating electromagnetic wave is parallel to the polarization direction of the rectangular line defect, the property of the line defect will be strengthened. Two separate line defects with a point defect between them can realize the properties of a straight complete line defect through the coupling between them. The bending properties of the line defect were investigated with the bending angle from 0 degrees to 90 degrees at 15 degrees interval. With the increasing of the bending angle, the guiding bandwidth was reduced slowly while the resonant intensity did not change too much. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3703569]