Fabrication of two-dimensional Ta_2O_5 photonic crystal slabs with ultra-low background emission toward highly sensitive fluorescence spectroscopy

Abstract

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°C 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.