James S. Wilkinson

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We present measurements of biomolecular binding reactions, using a new type of integrated-optical biosensor based on a planar directional coupler structure. The device is fabricated by Ag(+) - Na(+) ion exchange in glass, and definition of the sensing region is achieved by use of transparent fluoropolymer isolation layers formed by thermal evaporation. The(More)
The covalent attachment of DNA oligonucleotides onto crystalline silicon (100) surfaces, in patterns with submicron features, in a straightforward, two-step process is presented. UV light exposure of a hydrogen-terminated silicon (100) surface coated with alkenes functionalized with N-hydroxysuccinimide ester groups resulted in the covalent attachment of(More)
Selective excitation of spheroidal whispering gallery modes and bottle modes in a robust bottle microresonator fabricated straightforwardly from a short section of optical fiber is demonstrated. Characteristic resonance spectra of long-cavity bottle modes were obtained by using a tapered fiber to excite evanescently bottle microresonator at different points(More)
We have investigated the optical excitation and probing of bottle microresonators experimentally, using fiber tapers. The channel-dropping characteristics of such devices are shown to depend on the excitation configuration. In addition, the axial leakage behavior of these microresonators is characterized.
Electrochemical oxidation of the surface of a thin gold film overlaid on an optical waveguide and placed in a cell containing sulfuric acid is monitored by integrated optical surface plasmon resonance (IOSPR) combined with cyclic voltammetry. Waveguide transmittance correlates well with the charge transferred to and from the electrode to oxidize and reduce(More)
We demonstrate how a Y-branched optical waveguide can be used for microparticle sorting. Polystyrene microparticles, optically guided in the waveguide's evanescent field, are directed down the desired, more strongly illuminated, output branch. The output of a fibre laser at a wavelength of 1066 nm is coupled to the waveguide by direct butting. The power(More)
Micro-resonators have attracted considerable attention as a potential geometry for photonic devices used in multiplexing, memory and switching. These all-optical-resonators allow light at certain wavelengths to build up in intensity allowing nonlinear effects to be seen for much lower input power than in a bulk material. We report here on microspheres made(More)
A novel analytical system AWACSS (automated water analyser computer-supported system) based on immunochemical technology has been developed that can measure several organic pollutants at low nanogram per litre level in a single few-minutes analysis without any prior sample pre-concentration nor pre-treatment steps. Having in mind actual needs of(More)