Abstract
The goal of my thesis is to study the quasiparticle dynamics in YBCO films with the persistent photoinduced conductance effect. Our experiment contains two parts. In the first part, we use the resistance-temperature measurement to make sure the generation of the persistent photoconductivity in YBCO films illuminated by photons frequency doubled by diode laser (wave length 532 nm). In the second part, we use the time-resolved reflectivity system to measure the transient behaviors of quasiparticle in YBCO films and use the two temperature model and the Fermi surface -smearing theory to explain their dynamics. Our experiment can discover the different particle dynamics of YBCO films with the generation of the persistence photoconductivity .We propose the correctional model to explain the difference of the quasiparticle dynamics between semiconducting YBCO films of lower carrier concentration in our experiment and that of high carrier concentration in literature .We also find that the transient behavior change of the oxygen deficient YBCO films illuminated by photons is similar to that increased oxygen.