Femtosecond Optical Pulse Response of Y_(0.7)Pr_(0.3)Ba_2Cu_3O_(7-#delta#) Thin Films

摘要

We study Y_(0.7)Pr_(0.3)Ba_2Cu_3O_(7-#delta#) (YPBCO) thin films by a reflection pump-probe method with femtosecond optical pulses, and find that its response quite differs from that of a YBa_2Cu_3O_(7-#delta#) (YBCO) thin film. There are two components in the optical response triangle openR(t)/R in the superconducting state, which suggests that one component originates from the photoexcitation of the supercarriers while the other does from that of the normal carriers. We will discuss the temperature dependence of the carrier lifetime in the optically excited YPBCO in the normal and superconducting states.