Open AccessDetection of colored nanomaterials using evanescent field-based waveguide sensors
Author(s) -
Makoto Fujimaki,
Kohji Nomura,
Kazuki Sato,
Takafumi Kato,
Subash C.B. Gopinath,
Xiaomin Wang,
Kunio Awazu,
Yoshimichi Ohki
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.015732
Subject(s) - materials science , nanomaterials , biomolecule , optics , waveguide , nanoparticle , absorption (acoustics) , colored , refractive index , nanophotonics , optoelectronics , adsorption , signal (programming language) , nanotechnology , chemistry , physics , organic chemistry , computer science , composite material , programming language
We have developed an optical system designed for detecting colored nanomaterials in aqueous solutions, using the concept of evanescent-field-coupled waveguide-mode sensors. In this study, we found that the waveguide modes induced in the sensor are intrinsically sensitive to a change in optical absorption, or a 'change in color'. The system detects less than one gold nanoparticle (diameter: 20 nm) adsorbed per square micrometer. It is also demonstrated that significant signal enhancement due to adsorption of molecules is achieved using a dye. The developed sensor rarely suffers from a drawback of impurity adsorption. The system is expected to be applied as an effective sensing tool for metal colloids, nanoparticles, and colored biomolecules in solution.