References:
1. V. Bianchi, T. Carey, L. Viti, L. Li, E.H. Linfield, A.G. Davies, A. Tredicucci, D. Yoon, P.G. Karagiannidis, L. Lombardi, F. Tomarchio, A.C. Ferrari, F. Torrisi & M.S. Vitiello, “Terahertz saturable absorbers from liquid phase exfoliation of graphite” Nat. Commun. 8, 15763 (2017).