326 research outputs found
Grating-Coupled Surface Plasmon Resonance (GC-SPR) Optimization for Phase-Interrogation Biosensing in a Microfluidic Chamber.
Surface Plasmon Resonance (SPR)-based sensors have the advantage of being label-free, enzyme-free and real-time. However, their spreading in multidisciplinary research is still mostly limited to prism-coupled devices. Plasmonic gratings, combined with a simple and cost-effective instrumentation, have been poorly developed compared to prism-coupled system mainly due to their lower sensitivity. Here we describe the optimization and signal enhancement of a sensing platform based on phase-interrogation method, which entails the exploitation of a nanostructured sensor. This technique is particularly suitable for integration of the plasmonic sensor in a lab-on-a-chip platform and can be used in a microfluidic chamber to ease the sensing procedures and limit the injected volume. The careful optimization of most suitable experimental parameters by numerical simulations leads to a 30–50% enhancement of SPR response, opening new possibilities for applications in the biomedical research field while maintaining the ease and versatility of the configuration
Research activities arising from the University of Kent
In this paper I describe research activities in the field of optical fiber sensing undertaken by me after leaving the Applied Optics Group at the University of Kent. The main topics covered are long period gratings, neural network based signal processing, plasmonic sensors, and polymer fiber gratings. I also give a summary of my two periods of research at the University of Kent, covering 1985–1988 and 1991–2001
Single beam grating coupled interferometry: high resolution miniaturized label-free sensor for plate based parallel screening
Grating Coupled Interferometry (GCI) using high quality waveguides with two incoupling and one outcoupling grating areas is introduced to increase and precisely control the sensing length of the device; and to make the sensor design suitable for plate-based multiplexing. In contrast to other interferometric arrangements, the sensor chips are interrogated with a single expanded laser beam illuminating both incoupling gratings simultaneously. In order to obtain the interference signal, only half of the beam is phase modulated using a laterally divided two-cell liquid crystal modulator. The developed highly symmetrical arrangement of the interferometric arms increases the stability and at the same time offers straightforward integration of parallel sensing channels. The device characteristics are demonstrated for both TE and TM polarized modes. (C)2012 Optical Society of Americ
Microfluidics for plasmonic sensors
Ankara : The Program of Materials Science and Nanotechnology and the Institute of Engineering and Sciences of Bilkent University, 2009.Thesis (Master's) -- Bilkent University, 2009.Includes bibliographical references leaves 62-65.In this thesis, we integrate microfluidics with grating-coupled surface plasmon
configurations for sensing applications. First, in order to observe optimal
excitations, we introduce procedures for modification of the surface profiles of
gratings acquired from commercially available optical storage disks. A must
requirement in plasmonic systems, thin film metal deposition is performed. Soft
lithographic techniques are applied to coated disks to transfer the surface
topography of the disks to an elastomeric material, PDMS. Optical lithography is
used to fabricate microfluidic channels to where fluid will be injected. After
fabricating the final structure, ellipsometric measurement is used to investigate
the device performance. Experimental results were in consistence with the
theoretical simulations providing similar behaviours of reflection spectra. The
resonance wavelengths are found to be occuring very near to the expected values
along with high quality factors. However, to the device structure, an intensity loss
is observed which can be further improved. We achieved the tuning of the
resonance wavelength by changing the refractive index of the medium inside the
microchannel. Integration of the microfluidic channel to surface plasmon studies
may open up many applications such as biomolecular sensing.Ertaş, Yavuz NuriM.S
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