1. School of Clinical Engineering, Saitama Medical University, Yamane 1397-1, Hidaka, Saitama 350-1241, Japan
2. Department of Electrical and Electronic Engineering, Faculty of Engineering, Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585, Japan
3. Photon Science Center, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
4. HiLASE Centre, Institute of Physics ASCR, Za radnicí 828, 252 41 Dolní Břežany, Czech Republic
5. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan