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Ultrafast optical nonlinearity in quasi-one-dimensional Mott-insulator ${\rm Sr_2CuO_3}$

T. Ogasawara·M. Ashida·N. Motoyama·H. Eisaki·S. Uchida·Y. Tokura·H. Ghosh·A. Shukla·S. Mazumdar·M. Kuwata-Gonokami
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Abstract

We report strong instantaneous photoinduced absorption (PA) in the quasi-one-dimensional Mott insulator ${\rm Sr_2CuO_3}$ in the IR spectral region. The observed PA is to an even-parity two-photon state that occurs immediately above the absorption edge. Theoretical calculations 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 ${\rm Sr_2CuO_3}$ for all-optical switching.

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T. Ogasawara, M. Ashida, N. Motoyama, H. Eisaki, S. Uchida, Y. Tokura, H. Ghosh, A. Shukla, S. Mazumdar, M. Kuwata-Gonokami. 2000-06-05. Ultrafast optical nonlinearity in quasi-one-dimensional Mott-insulator ${\rm Sr_2CuO_3}$. https://doi.org/10.1103/physrevlett.85.2204

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