Optimization of angularly resolved Bloch surface wave biosensors

Abstract

Bloch surface wave (BSW) sensors to be used in biochemical analytics are discussed in angularly resolved detection mode and are compared to surface plasmon resonance (SPR) sensors. BSW supported at the surface of a dielectric thin film stack feature many degrees of design freedom that enable tuning of resonance properties. In order to obtain a figure of merit for such optimization, the measurement uncertainty depending on resonance width and depth is deduced from different numerical models. This yields a limit of detection which depends on the sensor's free measurement range and which is compared to a figure of merit derived previously. Stack design is illustrated for a BSW supporting thin film stack and is compared to the performance of a gold thin film for SPR sensing. Maximum sensitivity is obtained for a variety of stacks with the resonance positioned slightly above the TIR critical angle. Very narrow resonance widths of BSW sensors require sufficient sampling but are also associated with long surface wave propagation lengths as the limiting parameter for the performance of this kind of sensors.

Label-Free Detection of Tumor Angiogenesis Biomarker Angiopoietin 2 Using Bloch Surface Waves on One Dimensional Photonic Crystals

“…Based on the refractive indices of the selected materials at the wavelength of operation λ 0 , we designed 1DPC stacks accord- ing to the optimization procedures published elsewhere [23]. The optimization was carried out for TE polarized BSW; nevertheless in the following we also describe the TM polarized BSW sustained by the same biochip.…”

Biosensing platform combining label-free and labelled analysis using Bloch surface waves

“…Using such values enables one to optimize the stacks according to the considerations published elsewhere 9 . The final structure of the stack is shown in Figure 2 and has been previously applied for an ellipsometric sensing approach 16 .…”

“…Furthermore, BSW sensors offer the possibility to optimize the resonance, i.e., to tune its position and width as the most important parameters. Utilizing appropriate merit functions 8 allows optimizing the 1D-PC stack for optimum label-free operation 9 . However, label-free sensing might still suffer from less-than-ideal suppression or referencing of unspecific effects and yield a non-adequate limit of detection in the small concentration range of the analytes.…”

Label-free and fluorescence biosensing platform using one dimensional photonic crystal chips

“…BSW biosensors feature very low angular resonance widths compared to that of SPR, due to the low losses in the dielectric stacks 5 . Furthermore, the optimization of the 1D-PC stack, in terms of geometry and materials, offers the possibility to improve the label-free operation, by tuning the resonance position and width 6,7 .…”

“…Using such values enables one to optimize the stacks for operation in water environment according to the considerations published elsewhere 7 . The final structure of the stack is shown in Figure 1(a), where the transverse intensity distribution for the BSW at 0 is also shown.…”