Fig. 2: THz third-harmonic generation in Bi2Te3.
From: Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators
Time-domain waveforms of the fundamental radiation electric field (a) and the third-harmonic field generated in Bi2Te3, and the Al2O3 substrate for reference (b). Amplitude spectra of the fundamental radiation and THG in Bi2Te3 and substrate (c).
