Formation of photonic crystals by femtosecond laser microfabrication

We report a novel photo-polymerization technique of well-defined three-dimensional (3D) layer-by-layer structures by two-photon absorption (TPA) in resins. By changing the structural parameters such as the rod diameter, pitch (intra-rod distance in plane) and angular orientation between neighbor planes different lattice types can be accomplished. This enables a systematic investigation of optical properties of photonic crystals (PhCs) made by TPA photo-polymerization. The solidified skeleton of PhC can be utilized as a mold to infiltrate solidifiable dye. Selective removal of the solidified resin can yield in a reverse PhC structures. When the defect-layer(s) are introduced into PhC during fabrication the PhC may act as a high-quality microcavity. A defect mode has been observed for the first time in thus-fabricated structures. Laser-microexplosion fabrication is another promising technique for the PhC and optical memory applications. To achieve an opening of a full-bandgap the media of high dielectric constant is of request (a high dielectric contrast is necessary).