Femtosecond relaxation kinetics of highly excited MNa** states in CaF2 at 3.2 eV and 4.7 eV
in: Applied Physics B-Lasers and Optics (2011)
Femtosecond (fs) laser pulses at variable delay times allowed to track the fast non-radiative transitions between the manifold of highly excited MNa** states to the lower lying fluorescent MNa* state in CaF2. Two distinct MNa** states of the manifold at 3.16 eV (MNa**2) and 4.73 eV (MNa**3) were populated using the second (SH) and third harmonics (TH) of fs laser light at 785 nm. The population kinetics of the fluorescent MNa* state in the 2 eV excitation energy range was revealed by depleting its fluorescence centered at 740 nm using fundamental NIR fs laser pulses. The related time constants for MNa**2,3 -> MNa* relaxation amounted to 1.0 ± 0.14 ps and 3.0 ± 0.3 ps upon SH and TH excitation, respectively.