title: Large third-order optical nonlinearity of Cu-O chains investigated by third-harmonic generation spectroscopy.
abstract: Spectra of the third-order nonlinear susceptibility chi((3)) have been investigated for one-dimensional Mott insulators, Sr(2)CuO(3) and Ca(2)CuO(3), by applying the third-harmonic generation (THG) spectroscopy on their single-crystalline thin films. The three-photon resonance to the lowest charge-transfer (CT) state with odd parity strongly enhances chi((3)), which is of the order of 10(-9) esu. The two-photon resonant structure unravels the even-CT state, located close to the odd-CT state. Two types of chi((3)) spectra obtained from THG and the electroreflectance measurements are explained based on the concept of spin-charge separation.
authors.affiliation: Department of Advanced Materials Science, University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kishida
authors.forename: M
authors.initials: M
authors.lastname: Ono
authors.forename: K
authors.initials: K
authors.lastname: Miura
authors.forename: H
authors.initials: H
authors.lastname: Okamoto
authors.forename: M
authors.initials: M
authors.lastname: Izumi
authors.forename: T
authors.initials: T
authors.lastname: Manako
authors.forename: M
authors.initials: M
authors.lastname: Kawasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Taguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura
authors.forename: T
authors.initials: T
authors.lastname: Tohyama
authors.forename: K
authors.initials: K
authors.lastname: Tsutsui
authors.forename: S
authors.initials: S
authors.lastname: Maekawa