Abstract
An integrated optical detection device utilizing optical absorption and nonradiative relaxation (photothermal effect) was developed. The device consists of an optical waveguide with a Mach-Zehnder interferometer shape and a microfluidic channel which are integrated on a glass chip. The device showed a limit of detection of 15 μM in a 5-μm deep microchannel. This study will contribute to the studies of integrated devices of fluidics, optics and even electronics on chips.