1) Mrs. P.A. Subha, Department of Physics, has been awarded the Degree of Doctor of Philosophy in Physics from Cochin University of Science and Technology (CUSAT) under the guidance of Dr.V.C.Kuriakose, Professor (Retd.), Department of Physics, CUSAT, for the thesis entitled "Studies on Spatial and Temporal Solitons with Varying Dispersion Diffraction and Nonlinearity"
Abstract of the thesis
Optical solitons are special kind of optical pulses that can propagate undistorted over long distances and remain unaffected after collision with each other. The field of optical solitons has grown enormously due to its potential applications in communication, all optical switching, logic gates etc. The thesis presents a study of optical soliton propagation in inhomogeneous single mode and coupled fibres and the stabilization of multidimensional spatial solitons. The studies on single mode inhomogeneous fibres resulted evolving pulse compression mechanisms that produce a train of ultra short pulses, whereas the studies on the propagation of optical solitons in two mode nonlinear directional coupler have great importance due to their application for all-optical soliton steering and switching.
2) Mr. K.K.Abdullah, Department ofPhysics, has been awarded the Degree of Doctor of Philosophy in Physics from the University of Calicut for the thesis entitled "Studies on X-ray Interactions near K-edge using 241Am source and Proton Induced X-ray Emission(PIXE)". The research work was carried out under the guidance of Dr.K.Muraleedhara Varier, Professor, Department of Physics, University of Calicut.
Abstract of the thesis
X-ray attenuation coefficients and cross-sections are of great significance in both applied and fundamental science. They are invaluable in many applied fields, such as nuclear diagnostics, radiation protection, nuclear medicine, radiation dosimetry. In recent years, there has been renewed interest in the measurement of photon interaction cross-sections at low energies, especially energies close to absorption edges of elements. In the research work carried out, X-ray attenuation coefficients are determined at different energies around K-edge of few elements using 241Am source. Attenuation measurements were also done for some simple thin foil samples using radioactive source and compared with the technique of Proton Induced X-ray Emission. Since anomalous scattering factors of X-ray resonant scattering changes remarkably near an absorption edge of an atom in the energy region of present interest, the anomalous scattering factors were also derived for few elements from the attenuation measurements.
