title: Causality-based method for determining the time origin in terahertz emission spectroscopy.
abstract: We propose a method for determining the time origin on the basis of causality in terahertz (THz) emission spectroscopy. The method is formulated in terms of the singly subtractive Kramers-Kronig relation, which is useful for the situation where not only the amplitude spectrum but also partial phase information is available within the measurement frequency range. Numerical analysis of several simulated and observed THz emission data shows that the misplacement of the time origin in THz waveforms can be detected by the method with an accuracy that is an order of magnitude higher than the given temporal resolutions.
authors.affiliation: Department of Applied Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. unuma@nuap.nagoya-u.ac.jp
authors.forename: Takeya
authors.initials: T
authors.lastname: Unuma
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ino
authors.forename: Kai-Erik
authors.initials: KE
authors.lastname: Peiponen
authors.forename: Erik M
authors.initials: EM
authors.lastname: Vartiainen
authors.forename: Makoto
authors.initials: M
authors.lastname: Kuwata-Gonokami
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Hirakawa
mesh_terms: D008962:Models, Theoretical; D055053:Terahertz Radiation; D055068:Terahertz Spectroscopy / Q000379:methods*; D013995:Time