1. Hannover Centre for Optical Technologies, Institute for Transport and Automation Technology (Faculty of Mechanical Engineering), and Cluster of Excellence PhoenixD, Leibniz University Hannover, 30167 Hannover, Germany
2. Department of Electronics and Electrical Communications, Menoufia University, Menouf 32952, Egypt
3. Department of Applied Physics and Electronics, Umeå University, SE-901 87 Umeå, Sweden