Observation of room-temperature high-energy resonant excitonic effects in graphene

I. Santoso,1,3,4,9 P. K. Gogoi,1,2 H. B. Su,5 H. Huang,2 Y. Lu,2 D. Qi,1,2,3 W. Chen,2,4 M. A. Majidi,1,2 Y. P. Feng,1,2 A. T. S. Wee,1,2 K. P. Loh,1,4 T. Venkatesan,1,2 R. P. Saichu,6,7 A. Goos,6,7 A. Kotlov,8 M. Rübhausen,1,6,7 and A. Rusydi1,2,3,6,7,* 1NUSNNI-Nanocore, National University of Singapore, Singapore 117576 2Department of Physics, National University of Singapore, Singapore 117542 3Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 4Department of Chemistry, National University of Singapore, Singapore 117543 5Division of Material Science, Nanyang Technical University, 50 Nanyang Avenue, Singapore 639798 6Institut für Angewandte Physik, Universität Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany 7Center for Free Electron Laser Science (CFEL), Notkesstrasse 85, D-22607 Hamburg, Germany 8Hamburger Synchrotronstrahlungslabor (HASYLAB) at Deutsches Elektronen-Synchrotron (DESY), Notkesstrasse 85, D-22603 Hamburg, Germany 9Jurusan Fisika, Universitas Gadjah Mada, BLS 21 Jogyakarta, Indonesia (Received 26 December 2010; published 10 August 2011)