Abstract

All optical switching (AOS) is indispensable for the next generation terabit/s photonic networks. To implement AOS devices in practice, half-gap nonlinearity (HGNL) should be utilized, since real carrier excitation degrades AOS efficiency. No materials with strong HGNL for practical use have been found yet. Electron correlation effects, which have attracted much interest after the discovery of high temperature superconductivity and manifest themselves in anomalous transport and/or magnetic phenomena, can also be found in optical nonlinearity of so-called “strongly correlated electron systems” [1-5]. In particular, we have recently discovered enhanced HGNL of one-dimensional (1D) Mott insulator Sr₂CuO₃ in near-infrared (IR) region 1, 3]. To investigate the HGNL mechanism of this material, here we perform sub-picosecond pump-probe transmission measurements in near- and mid-IR region of 0.1-1eV. We have found strong interband two-photon absorption (TPA) in near-IR region and transient absorption in mid-IR region.

© 2002 Optical Society of America