Micro-sized void spheres are successfully generated in a solid polymer by use of a tightly focused femtosecond laser beam from a high-repetition-rate laser oscillator. Confocal reflection images show that the void spheres are longitudinal rotational symmetric ellipsoids with a ratio of long to short axes of approximately 1.5. Layers of void spheres are then stacked to create three-dimensional diamond-lattice photonic crystals. Three gaps are observed in the  direction with a suppression rate of the second gap of up to approximately 75% for a 32-layer structure. The observed first- and second-order gaps shift to longer and shorter wavelengths, respectively, as the angle of incidence increases.
© 2004 Optical Society of America
(140.7090) Lasers and laser optics : Ultrafast lasers
(160.4760) Materials : Optical properties
(160.5470) Materials : Polymers
(220.4000) Optical design and fabrication : Microstructure fabrication
(300.6340) Spectroscopy : Spectroscopy, infrared
Guangyong Zhou, Michael James Ventura, Michael Ross Vanner, and Min Gu, "Use of ultrafast-laser-driven microexplosion for fabricating three-dimensional void-based diamond-lattice photonic crystals in a solid polymer material," Opt. Lett. 29, 2240-2242 (2004)