Ultrafast nonlinear optics of PbS quantum dot-doped films

Summary form only given. We measure optical switching in zirconia-ormosil and polyvinyl alcohol (PVA) films doped with PbS quantum dots. Zirconia-ormosil films doped with 10 mol% of PbS were synthesized, in which the PbS nanoparticles have a mean diameter of 4.8 nm with a standard deviation of 0.8 nm. PVA films were synthesized using a similar method having the same concentration and same particle size. We use a pump-probe technique with 150 fs pulses at 800 nm (pump) and 1500 nm (probe) from an optical parametric amplifier for studying the dynamics of electronic decay on a short time scale. Pumping at much higher energies than the bandgap allows stronger coupling and higher carrier densities to be achieved.