Dai, S.
Ma, Q.
Andersen, T.
Mcleod, A. S.
Fei, Z.
Liu, M. K.
Wagner, M.
Watanabe, K.
Taniguchi, T.
Thiemens, M.
Keilmann, F.
Jarillo-Herrero, P.
Fogler, M. M.
Basov, D. N.
Article History
Received: 24 December 2014
Accepted: 19 March 2015
First Online: 22 April 2015
Competing interests
: F.K. is one of the co-founders of Neaspec and Lasnix, producer of the s-SNOM and infrared source used in this work. The remaining authors declare no competing financial interests.