Ultrafast dynamics of the Mnd-dtransition on hexagonal HoMnO3

The photoinduced changes in reflectivity (ΔR/R) at energies closed to the Mn d-d optical transition of HoMnO3 single crystal have been systematically measured from 300 K to 30 K by time-resolved optical pump-probe spectroscopy. The oscillation induced by the propagation of strain pulse was clearly observed in the ΔR/R signal with various probing wavelength. Moreover, the different relaxation processes of photoexcited carriers with in various wavelengths may be led by the blue shift of Mn3+ d level.