1. Center for Research and Education in Optical Sciences and Applications, Department of Applied Mathematics and Theoretical Physics, Delaware State University, Dover, DE 19901-2277, USA
2. Department of Telecommunications, Faculty of Electronic Engineering, University of Nis, Aleksandra Medvedeva 14, 1800, Nis, Serbia
3. Center for Research and Education in Optical Sciences and Applications, Department of Physics and Pre-Engineering, Delaware State University, Dover, DE 19901-2277, USA