1. Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziadzka 5, 87-100 Toruń, Poland
2. Univ. Rennes, CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, Rennes F-35000, France
3. Institute of Physics, Kazimierz Wielki University, ul. Powstańców Wielkopolskich 2, 85-090 Bydgoszcz, Poland