Su-Won Jang

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.

Refractive index change by photoinduction of a UV-sensitive SMF-to-PWG coupler

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 /spl Delta/n=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.

The Micro-Optic Mach-Zehnder Interferometry : Application to the UV Sensors

We propose and demonstrate the UV sensor based on micro-optic Mach-Zehnder interferometer composed of two single mode fiber-pigtailed collimators and a polymer film with photochromic dye. Spirooxazine is used as a UV sensing material which is dispersed in polystyrene and coated on the glass substrate by spin coating method. The extinction ratio and the spectral position of minimum transmission wavelength of fabricated UV sensor can be controlled to be more than 28 dB and 50 nm, independently. The experiment was conducted to measure the wavelength shift of spectral response with UV radiation using the spirooxazine concentration in polystyrene 1.0 wt% and 1.5 wt%. Fabricated UV sensors have a sensitivity of 0.162 nm/mW and 0.316 nm/A.U respectively.

Fabrication and characteristics of photofunctional polymer waveguide-type UV sensor

Single-mode planar waveguide type UV sensor was fabricated using SU-8 and photochromic dye. Polymer waveguide was fabricated 10 µm width and 2 µm thickness for single-mode operation. The UV sensor had an absorbance with 0.0396~0.114 absorbance/mW respectively when the 5 mm sensing area was irradiated with UV for 3 sec. And sensor had a linear properties by sensing area variation. Proposed single-mode sensor had more excellent properties of UV sensitivity than other UV sensors.

Light addressable potentiometric penicillin sensor using Ta 2 O 5 sensing membrane

In this study, the light addressable potentiometric sensors (LAPS) with , and structures were fabricated. The penicillinsae was immobilized on the devices to hydrolyze the penicillin using self-assembled monolayer (SAM) method. Then response characteristics according to the penicillin concentrations were measured and compared. The measuring system was simplified by using LabVIEW. The pH response characteristics of fabricated devices are 56 mV/pH ( sensing membrane) and 61 mV/pH ( sensing membrane). The sensitivity of sensor by enzyme reaction result of the enzyme reaction were 60 mV/decade and 74 mV/decade for and structure, respectively, in the range of of the penicillin concentration.

Light-addressable potentiometric penicillin image sensor using the self-assembled monolayer immobilizing method

In this study, the LAPSs (light addressable potentiometric sensors) which have devices of Si/sub 3/N/sub 4//SiO/sub 2//Si, Ta/sub 2/O/sub 5//SiO/sub 2//Si structure were fabricated. Also, it was investigated the response characteristics to penicillin concentration and detected the 2D images of 128 /spl times/ 128 pixels. The penicillinase was immobilized on the devices to hydrolyze the penicillin using self-assembled monolayer (SAM) method. The measuring system was simplified by using Lab VIEW software. The result of the enzyme reaction, the sensitivity of the sensor which has Si/sub 3/N/sub 4/ surfaces was 60 mV/decade and Ta/sub 2/O/sub 5/ surfaces was 74 mV/decade in the range of 0.1 mM /spl sim/ 10 mM of the penicillin concentration. Image detecting time by an enzyme reaction between penicillin and penicillinase took about 10 minutes at 128 /spl times/ 128 pixels in 1 /spl times/ 1 cm sensing area.

Side Polished Fiber Optic UV Sensor Using Evanescent Coupling of Photo-Functional Polymer

In this paper, we investigated a novel UV sensor using evanescent field coupling between the side polished fiber and photo-functional polymer waveguide. It was found that resonant wavelength shifts occur due to variation in the refractive index of polymer planar waveguide for its photo-functional properties on exposed UV. Spiroxazine (photochromic dye) was used as the planar waveguide. The resonant wavelength responses were exhibited at 1.44 nm/mW, 1.64 nm/mW, and 1.78 nm/mW when UV irradiations were exposed for 20 seconds, 30 seconds, and 40 seconds, respectively. The recovery time of sensor was independent of UV exposure power and 90% recovery time was 100 seconds.

Micro-optic temperature sensor based on a Mach-Zehnder interferometer

A novel optical temperature sensor has been proposed and demonstrated employing a micro-optic Mach-Zehnder interferometer. The temperature-to-wavelength conversion sensitivities of the fabricated sensors were from -0.1896 to -0.1720 nm/degC.

Corrections to "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.

Corrections to "Refractive Index Change by Photoinduction of a UV-Sensitive SMF-to-PWG Coupler"

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 /spl Delta/n=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.