Production of the Near-Infrared Spectrofluorophotometer and Fluorescence Quantum Yield of the Cyanine Solution for Dye Laser
Masao Ohtsuka, Toshiki Kudo, Masanobu Oguchi
and Hideto Ide*
Tokyo Institute of Polytechnics, 1583, Iiyama, Atugi, Kanagawa, 243-02 Japan
* College of Science & Engineering, Aoyama Gakuin University, 6-16-1, Chitosedai, Setagaya-ku, Tokyo, 157 Japan
For the accurate measurement of fluorescence quantum yield of biological dyes, dye lasers, etc., a spectrofluorophotometer with a built-in quantum counter is used. Such spectro meters that are available at the market can be used for exciting wavelengths of up to 600nm for which a quantum counter functions correctly, but not for longer wavelengths. In this study, light quantum counter dyes that can be used for exciting light of up to 700nm have been examined with the use of eight types of dye solutions, and it has been discovered that methylene blue trihydrate is the most suitable. By using this quantum counter dye, an electric control circuit of quantum counters has been constructed, consisting of the negative feed back circuit and the photomultiplier, and verified to be a spectrofluorophotometer that is usable from the practical points of view. In addition, with regard to several types of cyanine dyes, a comparative study of their energy levels obtained by a molecular orbital method, measured fluorescence quantum yield, and dye laser outputs has been conducted to evaluate those cyanine dyes as laser dyes.