[show abstract][hide abstract] ABSTRACT: 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 ∼ 0.114 absorbance/mW and 1 ∼ 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.
[show abstract][hide abstract] ABSTRACT: We fabricated a UV-sensitive photofunctional device using evanescent field coupling between a side-polished single-mode optical fiber (SMF) and photochromic dye-dispersed polymer planar waveguide (PWG). PWG was made by diarylethene derivative [1,2-bis(2,5-dimethylthiophen-3-yl) hexafluoro-cyclopentene (DM-BTE)] with a stability and memory effect by photoinduction. The wavelength response characteristic for UV irradiation time was 3.44 nm (UV irradiation time 60 s), and recovery time was 140 s. The optical attenuation characteristic of 1310-nm wavelength was 0.4 dB in 1 wt% concentration of DM-BTE and 1.65 dB at 10 wt% DM-BTE. The refractive index changes of DM-BTE by photoinduction were Δn=0.00067 in the condition of 3 wt% of DM-BTE concentration and 5 mW of UV intensity and 70 s of UV irradiation time.
[show abstract][hide abstract] ABSTRACT: ZnO thin films are prepared on the glass, GaAs (100), Si(111), and Si(100) substrates at different temperatures by the pulsed laser deposition (PLD) method. X-ray diffraction (XRD) measurements indicate that the substrate temperatures of 200–500, 200–500, 300–500, and 300–500 °C are the optimized conditions of crystalline for the glass, GaAs (100), Si (111), and Si (100) substrates, respectively. In spite of the films deposited on the different substrates, the films always show (002) orientation at the optimized conditions. Photoluminescence (PL) results indicate that the thin films fabricated at the optimized conditions show the intense near band PL emissions. The optimized conditions for PL are 500, 500, 400–500, and 500 °C for glass, GaAs (100), Si (111), and Si (100) substrates, respectively.