Open AccessAmplified molecular detection sensitivity in passive dielectric cavity
Author(s) -
De He,
Shixing Guo,
Lu Liu,
Tieyan Zhang,
Yadong Jiang,
Jimmy Xu,
Zhijun Liu
Publication year - 2018
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.032026
Subject(s) - materials science , optics , dielectric , plasmon , polarization (electrochemistry) , total internal reflection , surface plasmon , lithography , spectroscopy , optoelectronics , chemistry , physics , quantum mechanics
Vibrational absorption spectroscopy presents an effective and direct way for molecular detection and identification. In this paper, we propose and demonstrate a simple strategy and structure to amplify molecular detection sensitivity via the example of a monolayer octadecanethiol (ODT). The underlying amplification mechanism operates on both the enhanced surface field in and the coupled-oscillators' energy transfer between the molecules and the cavity underneath. The structure is designed to be simple and free of lithography or patterning with the potential for large-scale uses. It is made of just a quarter wavelength thick dielectric (ZnSe) layer atop a metallic reflecting base. Both angle and polarization dependent reflection spectra reveal signatures of CH 2 and CH 3 vibrations in theory and experiment. A vibrational signal intensity of 8.54% reached in s-polarization at a large incident angle is comparable to those reported in plasmonic nanostructures with greater sophistications in structure.