Highly sensitive detection of transient absorption in dye-doped ultrathin polymer films by the TiO(2)/K(+) composite optical waveguide method upon pulsed laser excitation

Toshihiko Nagamura; Tatsuo Adachi; Kyoichi Sasaki; Hideki Kawai; Xiao-Min Chen; Kiminori Itoh; Masayuki Murabayashi

doi:10.1016/j.talanta.2004.04.042

Highly sensitive detection of transient absorption in dye-doped ultrathin polymer films by the TiO(2)/K(+) composite optical waveguide method upon pulsed laser excitation

Talanta. 2005 Mar 15;65(5):1071-7. doi: 10.1016/j.talanta.2004.04.042. Epub 2004 Dec 15.

Authors

Toshihiko Nagamura¹, Tatsuo Adachi, Kyoichi Sasaki, Hideki Kawai, Xiao-Min Chen, Kiminori Itoh, Masayuki Murabayashi

Affiliation

¹ Department of Applied Chemistry, Faculty of Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan; Molecular Photonics Laboratory, Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8011, Japan.

PMID: 18969914
DOI: 10.1016/j.talanta.2004.04.042

Abstract

A composite optical waveguide (OWG) composed of a 10-18nm thick titanium dioxide (TiO(2)) film sputtered on a conventional K(+)-doped optical waveguide was first applied to detect transient absorption of organic dyes in ultrathin polymer films upon excitation with ns laser. The thickness of the TiO(2) film considerably affected the relative sensitivity of the composite OWG. The composite OWG with 10nm thick TiO(2) gave much stronger transient absorption for 30-415nm thick polymer films containing organic dyes than that with 18nm TiO(2). Transient absorption of phthalocyanine and spiropyran in 20-135nm thick polymer films was detected 3-20 times more sensitively by the composite OWG with 10nm TiO(2) than the conventional K(+)-doped OWG which showed a 150-fold sensitivity as compared with the usual normal incidence method. The relative sensitivity of the composite waveguide was also affected by the thickness and refractive index of polymers.