Shinzo Muto

A plastic optical fibre sensor for real-time humidity monitoring

Certain kinds of cellulose, such as a hydroxyethylcellulose, swell in a humid atmosphere and show a decrease in refractive index. Using this effect, a simple optical humidity sensor with fast response and high sensitivity, which is based on the plastic optical fibre structure change from leaky to guided, was easily fabricated and could be used for real-time humidity monitoring.

Plastic optical fibre sensor for detecting vapour phase alcohol

New plastic optical fibre sensors for detecting alcohol vapour have been studied. A certain kind of polymer such as a Novolac resin causes swelling when it is exposed to alcohol vapour. This effect produces a change in the polymer refractive index. Based on this principle, the plastic optical fibre (POF) type sensor head was fabricated by coating Novolac-resin and Novolac/Fe:SO complex film as a cladding layer on the plastic fibre core. When this sensor head was exposed to ethanol and methanol vapour, the light intensity passing through the sensor head changed remarkably depending on the vapour pressure. The sensor response was also found to be fast, stable and reproducible.

Simple Gas Sensor Using Dye-Doped Plastic Fibers

We report the fully optical sensing of low-level alkalescent gas and acid gas realized by the combination of dye-doped plastic fibers operating as the gas sensitive fiber and the fiber light source. This simple system was demonstrated to be capable of achieving a detection sensitivity below 10 ppm for both of ammonia and hydrochloride gases.

Nonlinear optical and XPS properties of Au and Ag nanometer-size particle-doped alumina films prepared by the sol–gel method

Abstract Au and Ag nanometer-size particle-doped alumina films were prepared by the aqueous sol–gel method. Their XPS and third-order nonlinear optical properties were examined. The XPS results gave evidence of an interaction between Au and alumina. Third-order susceptibilities, χ(3) and χ(3)/α obtained by degenerate four-wave mixing method were in the order of 10−8 esu and 10−10 esu.cm for doped films, respectively.

Fiber humidity sensor using fluorescent dye-doped plastics

The humidity-sensing optical fiber consists of a glass core and polymer clad doped with umbelliferon dye. Under UV light pumping. the blue fluorescence intensity from this fiber increases linearly with increasing relative humidity in the range of 20 to 80%RH. In addition. it has a fast response time and is not influenced by the presence of NH3 gas or HCl gas.

Optical Stabilizer and Directional Coupler Switch Using Polymer Thin Film Waveguides with Liquid Crystal Clad

Two types of optical functional devices with a polymer thin film core and liquid crystal clad, to which an electric voltage can be applied, have been fabricated. One type operates as an optical stabilizer and the other operates as an optical directional coupler switch since laser light propagation in these devices can be controlled electrically.

Preparation of a transparent alumina film doped with fluorescence dye and its energy transfer laser emission

Abstract A transparent alumina film was prepared from an aqueous sol by the sol-gel process. Changes in the fluorescence of 7-azaindole were monitored during the processing from the aqueous sol to the dried gel by dehydration. Coumarin 1, which is insoluble in water, and an anionic dye, uranin, were doped into the film by utilization of surface-active reagents, Triton X-100 and cetyltrimethylammonium bromide respectively. This doped film exhibited energy-transfer-type laser emission by nitrogen laser pumping.

Nonlinear optical properties (SHG, THG) of N-(4-nitrophenyl)-l-prolinol doped alumina film prepared by a sol-gel process

Abstract Orientationally ordered microcrystallites of N-(4- nitrophenyl )- l -prolinol (NPP) were formed by incorporating NPP molecules in an alumina film that possesses a card pack structure which is derived through a sol-gel process. The resulting alumina film exhibits enhancement of second and third order nonlinear optical effects. The optimum conditions necessary to prepare the NPP-doped film were determined from measured enhancement.

Second harmonic generation in 2-methyl-4-nitroaniline-doped alumina films prepared by a sol-gel process

Abstract 2-methyl-4-nitroaniline (MNA) was doped into a transparent alumina film by a sol-gel process starting from AlCl3 · 6H2O. A surface-active reagent, cetyl trimethyl ammonium bromide, was utilized in solubilizing MNA into the sol. Poling or co-doping of p-nitroaniline enhanced the intensities of second harmonic waves radiated from the doped films.

Magneto‐optical properties of transparent plastic material

The measured values of the Verdet constant of transparent plastic fiber materials such as the poly‐α‐methylstyrene and polystyrene are comparable to that of a NaCl crystal. In these magneto‐optical plastics, the wavelength giving the maximum value of the figure of merit for a fiber‐type optical isolator is about 500 nm. They are also used for constructing plastic fiber sensors for higher magnetic field or higher current.