A two-dimensional tantalum pentoxide (Ta₂O₅) photonic crystal (PC) slab with low-background emission was fabricated and a 12-fold enhancement of fluorescence from the organic dyes of perylene diimide adsorbed on the surface of the PCs was observed. The background emissions of the Ta₂O₅ substrates with and without the PCs after thermal annealing at 600℃ with oxygen gas were comparable to that of a well-cleaned cover glass. This is to date the lowest level of background emissions of two-dimensional PCs using materials with a high refractive index (>2). The results reported here provide new insights into the fabrication of the photonic devices that enable highly sensitive fluorescence microscopy or optical detections.

doi:10.1364/OE.19.001422.