Detection of colored nanomaterials using evanescent field-based waveguide sensors

Makoto Fujimaki*, Ken Ichi Nomura, Kazuki Sato, Takafumi Kato, Subash C.B. Gopinath, Xiaomin Wang, Koichi Awazu, Yoshimichi Ohki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)15732-15740
Number of pages9
JournalOptics Express
Issue number15
Publication statusPublished - 2010 Jul 19

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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