Dimensionality dependence of optical nonlinearity and relaxation dynamics in cuprates
نویسنده
چکیده
Femtosecond pump-probe measurements find pronounced dimensionality dependence of the optical nonlinearity in cuprates. Although the coherent twophoton absorption (TPA) and linear absorption bands nearly overlap in both quasi-one and two-dimensional (1D and 2D) cuprates, the TPA coefficient is one order of magnitude smaller in 2D than in 1D. Furthermore, picosecond recovery of optical transparency is observed in 1D cuprates, while the recovery in 2D involves relaxation channels with a time scales of tens of picoseconds. The experimental results are interpreted within the two-band extended Hubbard model. Transport and magnetic behavior of strongly correlated electron (SCE) systems, which depend on the lowest excitations, have been studied extensively in recent years. High energy electronic excitations, in contrast, have received less attention. Linear absorption studies,
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