Seminars and Events‎ > ‎Past Events‎ > ‎

Seminar Announcement: Wieslaw Strek

posted May 3, 2017, 1:45 PM by Stefano Varas   [ updated May 3, 2017, 1:45 PM ]

Tuesday, 2 May 2017, 11:00
Sala Grande Palazzina B via alla Cascata 56/C

"Laser Induced White Emission in Nanosized Materials"

Wieslaw Strek
Institute of Low Temperature and Structure Research, Polish Academy of Sciences
Wroclaw, Poland

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,
  • efficient photocurrent,
  • 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.

Stefano Varas,
May 3, 2017, 1:45 PM