1. Department of Physics and Electronics, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
2. Department of Physics and Electronics, Osaka Metropolitan University, Sakai, Osaka 599-8531, Japan
3. Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
4. Center for Quantum Information and Quantum Biology, Osaka University, Toyonaka, Osaka 560-8531, Japan