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Biomolecular sensors utilizing waveguide modes excited by evanescent fields
Author(s) -
FUJIMAKI M.,
ROCKSTUHL C.,
WANG X.,
AWAZU K.,
TOMINAGA J.,
IKEDA T.,
KOGANEZAWA Y.,
OHKI Y.
Publication year - 2008
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.2008.01907.x
Subject(s) - waveguide , materials science , substrate (aquarium) , refractive index , evanescent wave , optoelectronics , layer (electronics) , thin film , optics , thermal stability , excited state , nanotechnology , chemistry , oceanography , physics , organic chemistry , nuclear physics , geology
Summary Properties of evanescent‐field‐coupled waveguide‐mode sensors consisting of a multi‐layer structure made of a SiO 2 waveguide, a thin metal layer (Au, Cu, W or Ti), and a high refractive index glass substrate illuminated under the Kretschmann configuration have been theoretically and experimentally investigated. In all cases, reflectivity changes attributed to streptavidin combining to biotinyl groups were observed in close spectral vicinity of the waveguide resonances. The sensors with the Au and the Cu layers show superior sensitivity as compared to those with the W and the Ti layers, whereas the W and Ti layers show better thermal and chemical stability. The results indicate that the materials of thin metal layers should be chosen in accordance with the purpose of sensors and/or environment in which the sensors are used.