1. Physics of Magnetic and Photonic Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung Jl. Ganesha 10, Bandung 40132, Jawa Barat, Indonesia
2. Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jl. Raya Jatinangor Km.21, Sumedang 45363, West Java, Indonesia
3. Division of Electrical, Electronic and Information Engineering, Osaka University, Yamada-Oka 2-1, Suita, Osaka, Japan