Rapid fabrication of diamond-structured ceramic photonic crystals with graded dielectric constant and its controllable stop band properties

Three-dimensional (3D) inverse diamond-structured ceramic photonic crystals (PCs) were fabricated by stereolithography (SL) and gel-casting process using alumina slurry. The gradually varied solid loading in volume and its controllable stop band properties were studied in the PCs. It was found that, with the decrease ratio of the solid loading increasing, the stop band width decreased and the center frequency of the stop band shifted to the higher frequency range. Several PCs containing two graded solid loading of alumina simultaneously along the Г–Х 〈100〉 direction were also fabricated in the same process to investigate their complex stop band properties. Compared with the perfect PC, the stop band width of the graded solid loading PCs increased remarkably with the decrease ratio of the solid loading increasing when the electromagnetic wave transmits along the Г–Х 〈100〉 direction. When the decrease ratio reached to 10%, the stop band width reached 126.5% of that of the perfect PC, which agreed well with the Finite Integration Technique (FIT).