Nonlinear absorption of glass doped with PbS nanocrystals is studied and application of this composite material as a saturable absorber for mode locking in lasers is discussed. By using time resolved absorption pump-probe investigation, bleaching due to filling of discrete states caused by quantum confinement in the nanocrystals as well as induced absorption are revealed and characterized. The origin of the induced absorption is discussed. Kinetics of the transient absorption is studied. Two components observed in the decay of the nonlinearities are observed and interpreted in terms of the carrier trapping.
ASJC Scopus subject areas
- Physics and Astronomy(all)