Optical Dispersions of Bloch Surface Waves and Surface Plasmon Polaritons: Towards Advanced Biosensors.

Zigmas Balevicius,Algirdas Baskys

doi:10.3390/ma12193147

Abstract

The total internal reflection ellipsometry (TIRE) method was used for the excitation and study of the sensitivity features of surface plasmon polariton (SPP) and Bloch surface waves (BSWs) resonances. For the BSWs generation distributed Bragg gratings were formed on the tops of the substrates (BK7 glass substrate), which had six bilayers of ~120 nm SiO2 and ~40 nm TiO2 and 40 nm of TiO2 on the top. The SPP sample consisted of the BK7 glass prism and a gold layer (45 nm). Numerical calculations of the optical dispersions and the experimental TIRE data have shown that SPP resonance overtake the BSWs in wavelength scanning by a factor of about 17. However, for the ellipsometric parameters Ψ and Δ in the vicinity of excitations, the BSW sensitivity is comparable with SPP. The obtained resolutions were , for the SPP and , for the BSW. The capabilities of both surface excitations are discussed from the sensitivity point of view in the design of these advanced biosensors.

Highlights

Bloch surface waves (BSWs) are the type of surface electromagnetic waves, which can be excited on the surfaces of photonic crystals (PC) [1]
Summarizing, the total internal reflection ellipsometry (TIRE) method was used for the excitation and study of the sensitivity features of surface plasmon polariton (SPP) and BSW resonances
For the ellipsometric parameters Ψ and ∆ in the vicinity of excitations, the BSW sensitivity was comparable with SPP

Summary

Introduction

Bloch surface waves (BSWs) are the type of surface electromagnetic waves, which can be excited on the surfaces of photonic crystals (PC) [1]. The BSWs exist at the interface between the periodic dielectric structure with a distributed Bragg grating and the surrounding medium. Due to their optical dispersion features, the excitation of BSW can be tuned along a wide spectral range by changing the PC materials and the period of the bilayers [3]. It has been shown that BSW are suitable for fluorescence sensing applications. Being dielectrics, their surfaces do not quench the signal intensity as happens in the case of metals [4].

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Results

Conclusion