1. Precision and Intelligence Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
2. Keio Photonics Research Institute, Keio University, 7-1 Shinkawasaki, Saiwai-ku, Kawasaki 212-0032, Japan
3. Polytechnic School of Engineering, New York University, 6 MetroTech Center, Brooklyn, New York 11201, USA