Hybrid plasmonic slot waveguide with a metallic grating for on-chip biosensing applications

• Published in: Applied optics (2004) 2021-09, Vol.60 (25), p.7828
• Main Authors: Badri, S Hadi, SaeidNahaei, Sanam, Kim, Jong Su
• Format: Article
• Language: English
• Subjects: Bandpass filters; Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Biosensors; Bragg gratings; Equipment Design; Filtration - instrumentation; Finite difference time domain method; Lab-On-A-Chip Devices; Optical filters; Sensitivity; Silicon; Strip; Surface Plasmon Resonance; Waveguides
• ISSN: 1559-128X; 2155-3165
• DOI: 10.1364/AO.434927

Designing reliable and compact integrated biosensors with high sensitivity is crucial for lab-on-a-chip applications. We present a bandpass optical filter, as a label-free biosensor, based on a hybrid slot waveguide on the silicon-on-insulator platform. The designed hybrid waveguide consists of a narrow silicon strip, a gap, and a metallic Bragg grating with a phase-shifted cavity. The hybrid waveguide is coupled to a conventional silicon strip waveguide with a taper. The effect of geometrical parameters on the performance of the filter is investigated by 3D finite-difference time-domain simulations. The proposed hybrid waveguide has potential for sensing applications since the optical field is pulled into the gap and outside of the silicon core, thus increasing the modal overlap with the sensing region. This biosensor offers a sensitivity of 270 nm/RIU, while it only occupies a compact footprint of 1.03µ ×17.6µ .