Seminar Announcement: Wieslaw Strek
Data pubblicazione: 3-mag-2017 20.45.24
Tuesday, 2 May 2017, 11:00
Sala Grande Palazzina B via alla Cascata 56/C
"Laser Induced White Emission in Nanosized Materials"
Institute of Low Temperature and Structure Research, Polish Academy of Sciences
Laser induced white emission (LIWE) has been recently reported for a number of nanosized materials, such as: rare earth doped nanocrystalline powders, transparent undoped nanocrystals, and graphene composites. It was shown that LIWE is the broadband anti-Stokes emission characterized by several characteristic features:
threshold behavior on excitation density,
nonlinear dependence on excitation power P,
dependence on atmospheric pressure,
dependence on concentration of active ions,
dependence on temperature of sample,
low temperature of white emission,
long rise and decay times.
The examples of LIWE experimental results will be presented. A mechanism leading to white emission will be discussed in terms of avalanche multiphoton ionization and intervalence charge transfer transitions.