1. Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal 576 104, India
2. Centre for Applied Nanosciences, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal 576 104, India
3. Centre for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal 576 104, India