Matthews, Mary http://orcid.org/0000-0003-3683-1749
Morales, Felipe http://orcid.org/0000-0001-9066-633X
Patas, Alexander
Lindinger, Albrecht
Gateau, Julien
Berti, Nicolas
Hermelin, Sylvain
Kasparian, Jérôme http://orcid.org/0000-0003-2398-3882
Richter, Maria
Bredtmann, Timm
Smirnova, Olga http://orcid.org/0000-0002-7746-5733
Wolf, Jean-Pierre
Ivanov, Misha
Article History
Received: 8 December 2016
Accepted: 7 March 2018
First Online: 16 April 2018
Change Date: 18 June 2018
Change Type: Correction
Change Details: In the version of this Letter originally published, the units of the bottom three values in the Fig. 1d legend were incorrect; they should have been W cm<sup>–2</sup>. This has now been corrected.
Competing interests
: The authors declare no competing interests.