Experimental investigation of the propagation properties of bloch surface waves on dielectric multilayer platform

Abstract

Background: The periodic dielectric multilayers sustaining Bloch surface waves have been proposed as a platform for the sensing applications and the two dimensional integrated optics. In this paper, we present the experimental and theoretical investigation of propagation properties of Bloch surface waves, for example propagation length and refractive index of the surface mode, at the interface of a dielectric multilayer platform. We use thin layers (~λ/25) of titanium dioxide as an additional layer of high index material. Methods: We exploit multi-heterodyne scanning near-field optical microscopy and total internal reflection configuration as a near-field and far-field characterization tools. Results: The longest propagation length is achieved when the multilayer is designed to have the dispersion curve positioned close to the middle of the photonics band gap. We measure a Bloch surface wave mode of propagation length 3.24 mm and of an effective refractive index contrast 0.15. Conclusions: The experimental results are in conformity with theoretical results. This study paves a way to realize efficient and compact two dimensional components and systems.