Abstract

Progress towards understanding high transition- temperature superconductivity in the copper oxides (cuprates) is hindered by the coexistence of complex spin, charge and lattice degrees of freedom. Even in the undoped parent compounds a detailed microscopic description of excitations within the basic energy bandstructure as observed in electron and optical spectroscopies^1,2 remains a formidable task. Nonlinear optical spectroscopy, however, allows precise control over excitation energies and symmetries, revealing important new information about such systems.³

© 2001 Optical Society of America