The objective is to economically fabricate proof-of-principle prototypes of 3-D photonic band gap crystals, which are layer-by-layer (LBL) structured and have the band gap in the mid-infrared to visible range. Titanium dioxide (anatase phase) is used as the infilling materials due to its relatively high refractive index (n=2.5). The structure, which has a 2.5microm periodicity, shows distinctive optical properties. An FTIR microscopy study of a 4-layer LBL PBG structure has a characteristic peak in reflectance corresponding to the main bandgap at around 5.0microm wavelength with the peak intensity reaching 35%. An 8-layer structure gives 60% peak intensity and a 12-layer structure has 90% peak intensity. The structures also show the same bandgap effect at 5.0microm wavelength in the transmission spectra. Results show rutile phase titania (n=2.9) 4-layer structure has the reflectance intensity increased to 53% at the main peak position. 1-layer structure with 1microm periodicity was also been fabricated.
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