1. Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
2. Adavanced nanofabrication Imaging and characterization, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
3. National Center for Nanotechnology, King Abdulaziz City for Science and Technology (KACST), Riyadh 11442-6086, Saudi Arabia