1. Department of Physics, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
2. Department of Physics, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia V6T 1Z1, Canada
3. Laser Programme, Centre for Advanced Technology, Indore 452 013, India
4. Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada