An integrated optical sensor specifically sensitive to ozone has been developed by vacuum evaporating a tapered thin film of copper tetra--butylphthalocyanine (CuPct) through a mask onto a slab waveguide made by K+–Na+ ion-exchange in glass. A pair of photoresist gratings fabricated on the waveguide offer the sensor a good long-term stability in optical coupling. The evaporated dye film composed of CuPct H-aggregates has a large absorption at 633 nm and a high-index of refraction relative to that of glass substrates. Therefore, the waveguiding mode excited with a 633 nm laser beam in the CuPct film-coved waveguide is highly attenuated. The CuPct film is very stable in air but ozone exposure at room temperature can result in a rapid and irreversible decoloration of the film. In the presence of a given concentration of ozone in the ambient air about the senor, the output light intensity was detected to linearly increase with time. It has been demonstrated that the sensor containing a 15 mm long and tens-of-nanometers thick dye film can detect 33 ppb ozone in air at room temperature.
- PIE waveguide;
- Tapered film of CuPct;
- Ozone sensor;
- High selectivity;
- Low detection limit
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Zhi-mei Qi received the BSc degree in physics from Inner Mongolia University in 1991, the MSc degree in chemistry from the University of Science and Technology of China in 1994 and the DrEng degree from the Yokohama National University, Japan, in 2001. From 1994 to 1997, he joined State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences. From 2001 to 2003, he was a JST postdoctoral fellow and worked in Nanoarchitectonics Research Center, National Institute of Advanced Industrial Science and Technology (AIST). In 2003 he obtained another JST postdoctoral fellowship and transferred to the present institute (Energy Electronics Institute, AIST). His current research interests include the development of novel optical waveguide devices for chemical, biological and gas sensing applications.
Hao-shen Zhou received BSc degree from Nanjing University in 1985, MSc degree from Nanjing Electronic Device Institute in 1988. He was awarded a PhD by the University of Tokyo in 1994. He held a postdoctoral fellowship at RIKEN where he worked as a basic science researcher from 1994 to 1997. He is currently a senior researcher in the National Institute of Advanced Industrial Science and Technology (AIST).
Itaru Honma is the leader of the Energy Materials Group in the Energy Electronics Institute, National Institute of Advanced Industrial Science and Technology (AIST), Japan. He received a BSc degree from the University of Tokyo in 1984. He became a research assistant in the Department of Chemical Engineering of the University of Tokyo in 1985 and an assistant professor in 1991. He joined the Electrotechnical Laboratory in 1995 and has been investigating functional nanomaterials for use in relation to sustainable energy technology and environmental problems.
Kiminorio Itoh received the BEng degree in electrochemistry from Yokohama National University in 1973, the MEng and DrEng degrees from the University of Tokyo in 1975 and 1980, respectively. From 1978 to 1988, he served as a research associate and assistant professor of Faculty of Engineering at the University of Tokyo, and in 1988, he joined the Institute of Environmental Science and Technology, Yokohama National University as a Professor. He has been working on photochemistry and electrochemistry at solid surfaces. His current research interests include the application of optical waveguide techniques to surface chemistry, the analyses of both DNA in soil and global warming.
Hiroyuki Yanangi received the BSc and MSc degrees in organic synthesis from the Kyushu University in 1981 and 1983, respectively. He is presently a senior researcher at Tokuyama Corporation, Tokyo. His research interests cover the optical waveguide gas sensors, ionophores for ion selective electrodes and organic thin films used for chemical sensors.