title: Mechanism of elliptically polarized terahertz generation in two-color laser filamentation.
abstract: We investigate the mechanism of elliptically polarized terahertz (THz) pulse generation in femtosecond two-color laser-produced plasma. In the case of in-line laser focusing, we observe the THz polarization evolves from linear to elliptical with increasing plasma length. This ellipticity arises from two combined effects--successive polarization rotation of local THz plasma sources, caused by laser phase and polarization modulations, and the velocity mismatch between laser and THz, which produces an elliptical THz pulse from a series of time-delayed, polarization-rotating local THz fields.
authors.affiliation: Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Yong Sing
authors.initials: YS
authors.lastname: You
authors.forename: Taek Il
authors.initials: TI
authors.lastname: Oh
authors.forename: Ki-Yong
authors.initials: KY
authors.lastname: Kim