1. Physics Department, King Fahd University of Petroleum and Minerals, 31261 Dhahran, Saudi Arabia
2. Center of Research Excellence in Renewable Energy (CoRERE), Research Institute, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia
3. Laboratoire de Physique LPA, Ecole Normale Supérieure, 75231 Paris 5, France