Browsing by Subject "Forward scattering"

Now showing 1 - 3 of 3

Open Access
Analysis of edge waves due to a point source in the presence of a PEC wedge
(IEEE, 2014) Ghassemiparvin, Behnam; Altıntaş, Ayhan
In this paper, we investigate the behavior of the field in the paraxial region of a perfectly conducting wedge and analyze the guiding effect of the wedge. It is observed that as the wedge angle increases, the guidance effect of the wedge decreases and the scattered field in the paraxial region is maximum for the half plane. In addition, interaction of the edge waves with a spherical impedance scatterer is investigated. It is found that for the backscattering case, as the impedance mismatch between the spherical boss and the free-space increases the scattered field due to the boss increases. However for the forward scattering case, impedance of the boss does not affect the scattered field significantly.
Open Access
Femtosecond laser fabrication of fiber based optofluidic platform for flow cytometry applications
(SPIE, 2017) Serhatlioglu, Murat; Elbuken, Çağlar; Ortac, Bülend; Solmaz, Mehmet E.
Miniaturized optofluidic platforms play an important role in bio-analysis, detection and diagnostic applications. The advantages of such miniaturized devices are extremely low sample requirement, low cost development and rapid analysis capabilities. Fused silica is advantageous for optofluidic systems due to properties such as being chemically inert, mechanically stable, and optically transparent to a wide spectrum of light. As a three dimensional manufacturing method, femtosecond laser scanning followed by chemical etching shows great potential to fabricate glass based optofluidic chips. In this study, we demonstrate fabrication of all-fiber based, optofluidic flow cytometer in fused silica glass by femtosecond laser machining. 3D particle focusing was achieved through a straightforward planar chip design with two separately fabricated fused silica glass slides thermally bonded together. Bioparticles in a fluid stream encounter with optical interrogation region specifically designed to allocate 405nm single mode fiber laser source and two multi-mode collection fibers for forward scattering (FSC) and side scattering (SSC) signals detection. Detected signal data collected with oscilloscope and post processed with MATLAB script file. We were able to count number of events over 4000events/sec, and achieve size distribution for 5.95μm monodisperse polystyrene beads using FSC and SSC signals. Our platform shows promise for optical and fluidic miniaturization of flow cytometry systems. © 2017 SPIE.
Open Access
Metamaterial based cloaking with sparse distribution of spiral resonators
(SPIE, 2010) Guven, K.; Saenz, E.; Gonzalo, R.; Özbay, Ekmel; Tretyakov, S.
We investigate the application of a metamaterial that is formed by the sparse distribution of spiral resonators as an optical transformation medium is in order to achieve electromagnetic cloaking. The well-known Clausius-Mossotti formula relates the microscopic polarizability of a single resonant particle to the macroscopic permittivity and permeability of the effective medium. By virtue of transformation optics, the permittivity and permeability of the medium, in turn, can be designed according to a coordinate transformation that maps a certain region of space to its surrounding. As a result, the mapped region can be cloaked from electromagnetic waves. In this study, the spirals are optimized to exhibit equal permittivity and permeability response so that the cloak formed by these spirals will work for both the TE and TM polarizations. An experimental setup is developed to visualize the steady state propagation of electromagnetic waves within a parallel plate waveguide including the cloaking structure. The measured and simulated electromagnetic field image indicates that the forward scattering of a metal cylinder is significantly reduced when placed within the cloak. © 2010 SPIE.