THz Spectroscopy of Photogenerated Carriers in Fe:LiNbO3 for Optical Control of 2D Materials

We report on significant photo-induced changes in the transmission of THz radiation through iron doped lithium niobate (Fe:LiNbO
₃
). The effect is attributed to photo-excited charge carriers, originating from the Fe dopant energy levels in the band gap of the crystal. In previous work, we have demonstrated that Fe:LiNbO
₃
substrates allow control of graphene electronics and plasmonics through photo-induced electrostatic fields in the crystal [1]. THz time domain spectroscopy (TDS) measurements of Fe:LiNbO
₃
provide the means to calculate photoexcited charge carrier densities within the crystal, thereby providing further insight into Fe:LiNbO
₃
as a versatile platform for the transient photo-induced electrostatic doping of 2D materials.