1. Department of Physics, Durham University, South Road, Durham DH1 3LE, United Kingdom
2. Department of Material Science and Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom
3. Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland
4. Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
5. Łukasiewicz Research Network—Institute of Microelectronics and Photonics, Aleja Lotników 32/46, 02-668 Warsaw, Poland
6. Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom