1. Institute of Solid State Physics, University of Latvia, Kengaraga Str. 8, 1063 Riga, Latvia
2. Transparent Electro‐Active Materials Project, ERATO, Japan Science and Technology Agency, KSP C‐1232, 3‐2‐1 Sakado Takatsu‐ku, Kawasaki 213‐0012, Japan
3. Tokyo Institute of Technology, Yokohama 226‐8503, Japan