Gigantic optical nonlinearity in one-dimensional Mott-Hubbard insulators

Citation
H. Kishida et al., Gigantic optical nonlinearity in one-dimensional Mott-Hubbard insulators, NATURE, 405(6789), 2000, pp. 929-932
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary,Multidisciplinary,Multidisciplinary
Journal title
NATURE
ISSN journal
0028-0836 → ACNP
Volume
405
Issue
6789
Year of publication
2000
Pages
929 - 932
Database
ISI
SICI code
0028-0836(20000622)405:6789<929:GONIOM>2.0.ZU;2-T
Abstract
The realization of all-optical switching, modulating and computing devices is an important goal in modern optical technology. Nonlinear optical materi als with large third-order nonlinear susceptibilities (chi((3))) are indisp ensable for such devices, because the magnitude of this quantity dominates the device performance. A key strategy in the development of new materials with large nonlinear susceptibilities is the exploration of quasi-one-dimen sional systems(1,2), or 'quantum wires'-the quantum confinement of electron -hole motion in one-dimensional space can enhance chi((3)). Two types of ch emically synthesized quantum wires have been extensively studied: the band insulators of silicon polymers, and Peierls insulators of pi-conjugated pol ymers and platinum halides. In these systems, chi((3)) values of 10(-12) to 10(-7) e.s.u. (electrostatic system of units) have been reported(3-7). Her e we demonstrate an anomalous enhancement of the third-order nonlinear susc eptibility in a different category of quantum wires: one-dimensional Mott i nsulators of 3d transition-metal oxides and halides. By analysing the elect roreflectance spectra of these compounds, we measure chi((3)) values in the range 10(-8) to 10(-5) e.s.u. The anomalous enhancement results from a lar ge dipole moment between the lowest two excited states of these systems.