1. Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
2. Centre for Nanoscience and Nanotechnology, Department of Physics, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India
3. KAUST Catalysis Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
4. Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia