1. Research Center for Material Processing and Renewable Energy, Siliwangi University, Jl. Siliwangi, Tasikmalaya, Indonesia
2. Research Center for Development of Far Infrared Region, University of Fukui, Bunkyo, Fukui, Japan
3. Department of Applied Physics, Faculty of Engineering, University of Fukui, Bunkyo, Fukui, Japan
4. Lab. Plasma Physics and Engineering, Institute of Electronics of the Bulgarian Academy of Sciences and Association EURATOM-INRNE, Sofia, Bulgaria