Laser-assisted Fabrication of 3-D Structures on Polymer Film

3-D photonic bandgap (PBG) crystals were fabricated by laser assisted imprinting of self-assembled silica particles on polymer film. Pulses (pulse duration 23 ns) of a KrF excimer laser instantaneously heated the silicon substrate under polymer film, which transferred the heat to the polymer film and melted it. With the force applied on the quartz, the melted polymer infiltrated and solidified over the assembled silica particles. By removing silica particles embedded in the silicon using hydrofluoric acid, inverse-opal photonic crystal was produced. This technique enables us to fabricate micrometer-order deep structures and 3-D hemispherical cavities structures.