Experimental determination of the sensitivity of Bloch Surface Waves based sensors

Abstract

Detection of glucose in water solution for several different concentrations has been performed with the purpose to determine the sensitivity of Near Infrared Bloch Surface Waves (lambda = 1.55microm) upon refractive index variations of the outer medium. TE-polarized electromagnetic surface waves are excited by a prism on a silicon nitride multilayer, according to the Kretschmann configuration. The real-time reflectance changes induced by discrete variations in glucose concentration has been revealed and analyzed. Without using any particular averaging strategy during the measurements, we pushed the device detection limit down to a glucose concentration of 2.5mg/dL, corresponding to a minimum detectable refractive index variation of the water solution as low as 3.8.10(-6).

Detection of protein aggregation with a Bloch surface wave based sensor

“…The resolution of the system is ın = 1.24 × 10 −4 RIU. This is two orders of magnitude lower than the best SPR sensors [16], but is inherent to the design choices rather than the technique, that has been shown to reach much larger sensitivities [8]. The lower observed resolution is due to the angular resolution of the motors used in the angular scanning scheme.…”

“…Several authors have since shown experimentally their existence [4] and characterised their properties [5,6]. Moreover, due to the confinement of the wave at the surface, their use in a sensing scheme has been predicted and demonstrated [7][8][9][10][11]. Because of the periodic nature of the underlying structure, these waves are known as Bloch Surface Waves (BSW).…”

Two-dimensional polymer grating and prism on Bloch surface waves platform

“…Several works have been proposed and demonstrated including experimental determination of BSWs sensitivity [5], direct comparison of BSWs and SPPs sensors [6], and the experimentally achieved improvement of sensitivity with BSWs in comparison with SPPs [7]. Among the sensing applications, we may cite those reported on chemical and biosensing [8][9][10], gas sensing [11], and fluorescence emission enhancement [12,13].…”

Investigation of ultra-thin waveguide arrays on a Bloch surface wave platform

“…Due to their dielectric nature, BSW elements provide relatively lower losses and longer propagation distances. This property is of special interest for BSW-based 2D optical circuits or sensors [3][4][5]. This paper will focus on a waveguide coupler consisting of parallel ultra-thin polymer waveguides (thickness ∼λ∕15).…”