UV-sensitive photofunctional device using evanescent field absorption between SU-8 polymer optical waveguide and photochromic dye

We presented an ultraviolet (UV)-sensitive photofunctional device using a principle of evanescent field coupling occurring between SU-8 waveguide and photochromic dye (spirooxazine). The feasibility as a UV sensor was evaluated. When the 5-mm sensing area was irradiated with UV for 3 s, the absorption and the output intensity of the UV sensor was 0.0396 /spl sim/ 0.114 absorbance/mW and 1 /spl sim/ 10 mW, respectively. The UV sensor had linearity by variation of sensing area. The sensitivity of the proposed sensor was higher than the spectrophotometers method and optical fiber sensors.