Excitation of an electronic subsystem of YAG crystal with femtosecond laser pulses
Abstract
The temporal dynamics of refractive index change induced by intense femtosecond 800 nm laser radiation in a yttrium aluminum garnet (YAG) crystal was explored using pump-probe interferometry. Beyond the Kerr effect, only a positive laser-induced rise of permittivity was detected ( Δ n∼ +{{10}-3} ), whereas most of the material demonstrates a remarkable transient response opposite in sign to that assigned usually to free carrier generation. Observed dynamics of n indicates that (i) the possible formation of free electron-hole (e-h) pairs is totally masked and (ii) the formation of tightly bound electronic states (transient defects) takes time approximately equal to a pulse duration. We discuss whether the latter could be a direct light-induced process or still a result of the ultrafast decay of radiatively generated electron-hole pairs.
- Publication:
-
Laser Physics Letters
- Pub Date:
- June 2017
- DOI:
- 10.1088/1612-202X/aa6dd3
- Bibcode:
- 2017LaPhL..14f6002K