Ultrafast optical nonlinearity in the quasi-one-dimensional mott insulator Sr2CuO3
We report strong instantaneous photoinduced absorption in the quasi-one-dimensional Mott insulator Sr2CuO3 in the IR spectral region. The observed photoinduced absorption is to an even-parity two-photon state that occurs immediately above the absorption edge. Theoretical calculation based on a two-band extended Hubbard model explains the experimental features and indicates that the strong two-photon absorption is due to a very large dipole coupling between nearly degenerate one- and two-photon states. Room temperature picosecond recovery of the optical transparency suggests the strong potential of Sr2CuO3 for all-optical switching.
Ogasawara
T
Department of Applied Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Ashida
M
Motoyama
N
Eisaki
H
Uchida
S
Tokura
Y
Ghosh
H
Shukla
A
Mazumdar
S
Kuwata-Gonokami
M