Affiliation: | (1) Department of Applied Physics and Photonics, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050, Belgium;(2) Institute of Physics, Technical University of Lodz, ul. Wolczanska 219, Lodz, 93-005, Poland;(3) Institute of Solid State Physics, 72 Tzarigradsko Chaussee Blvd., Sofia, 1784, Bulgaria |