title: Detection of colored nanomaterials using evanescent field-based waveguide sensors.
abstract: 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.
authors: Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi Tsukuba 305-8562, Japan. m-fujimaki@aist.go.jp
authors: Makoto
authors: M
authors: Fujimaki
authors: Ken-ichi
authors: K
authors: Nomura
authors: Kazuki
authors: K
authors: Sato
authors: Takafumi
authors: T
authors: Kato
authors: Subash C B
authors: SC
authors: Gopinath
authors: Xiaomin
authors: X
authors: Wang
authors: Koichi
authors: K
authors: Awazu
authors: Yoshimichi
authors: Y
authors: Ohki