1. Unité de Dynamique et Structure des Matériaux Moléculaires, EA 4476, Université du Littoral Côte d'Opale, F-59140 Dunkerque, France
2. Liquid Crystal Research Lab, Physics Department, University of Lucknow, Lucknow, India
3. Nanoscience Laboratory, Department of Physics, National Institute of Technology, Durgapur, West Bengal, India
4. Department of Physics, Deshbandhu College (Delhi University), New Delhi, India