1. Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, São Paulo, Brazil
2. School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Centre, University of Nottingham, NG7 2RD Nottingham, United Kingdom
3. National Institute of Laser Enhanced Sciences, Cairo University, Egypt
4. Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Goteborg, Sweden
5. Leibniz-Institute for Crystal Growth, Max-Born-Str. 2, D-12489 Berlin, Germany