S-shaped SU-8 optical waveguide immobilized with gold nanoparticles for trace detection of explosives

摘要

In this study, we report a miniaturized optical sensor for direct detection of vapors of nitro-based explosives using gold nanoparticle (AuNP) coated SU-8 polymer optical waveguides. S-shaped waveguide geometry was chosen due its enhanced evanescent field sensitivity. Light was coupled into the waveguide structure to evanescently excite the localized surface plasmon resonance (LSPR) modes of the immobilized AuNP. The AuNP were functionalized with 4-mercaptobenzoic acid (4-MBA) which acts as the receptor for detecting nitro-based explosive. The AuNP coated SU-8 optical waveguide sensor demonstrated an ability to detect 10 parts per billion (ppb) concentration of explosive analytes.