抄録
We have developed a novel micro optical diffusion sensor based on a laser induced dielectrophoresis (LIDEP) enabling small sample volutme, high-speed measurement and on-site sensing. AC voltage is applied between transparent electrodes and two excitation lasers are intersected on the photoconductive layer. The light intensity distribution increases the electrical conductivity of the a-Si:H layer by photoconductive effect, and generates non-uniform electric field. As a result, the dielectrophoresis is induced. The concentration distribution is then induced by LIDEP force. The diffusion coefficient can be obtained by detecting the decay of the sinusoidal concentration distribution. In this paper, we report the validity of the measurement principle and observe the diffusion of the concentration distribution. The decay time of the diffusion of the concentration distribution agreed well with the theoretical calculation. As a result, the applicability of MODS as the diffusion coefficient measurement method was verified.
