1. Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
2. National Institute of Advanced Industrial Science and Technology (AIST), Nagoya, Aichi 463-8560, Japan
3. Department of Physics, Comilla University, Cumilla 3506, Bangladesh
4. National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8563, Japan