Photoinduced ultrafast optical anisotropy encountered by spin-flip transition in La0.67Ca0.33MnO3

Understanding and controlling the transient optical anisotropy of strong correlation systems is of great interest in the quest for information processing and storage. Here, we report on ultrafast optical pump-probe measurements with linearly and circularly polarized laser pulses in the manganite La0.67Ca0.33MnO3 thin film. We show both the time-resolved reflectivity and the polarization state (Kerr rotation and ellipticity) of the probe-pulse at different temperatures, which are analyzed by the ultrafast intersite transition between Mn3+ and Mn4+ sites at photon energies around 1.55 eV. During the temperature-induced dynamical spectral weight transfer, a spin-flip photo-Transition between spin up eg states of Mn3+ and spin down eg states of Mn4+ ions occurs and is imprinted on the optical anisotropy of the probe beam.