17 June 1993 Femtosecond optical nonlinearities in YBa2Cu3O7-x
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Proceedings Volume 1861, Ultrafast Pulse Generation and Spectroscopy; (1993) https://doi.org/10.1117/12.147068
Event: OE/LASE'93: Optics, Electro-Optics, and Laser Applications in Scienceand Engineering, 1993, Los Angeles, CA, United States
We have performed a series of femtosecond reflectivity experiments on various YBa2Cu3O7-x (YBCO) thin films at temperatures ranging from 12 K to 300 K. In particular, we have measured the dependence of the transient reflectivity signal on probing laser frequency, oxygen content, sample's thickness, ambient temperature, and pumping laser intensity. Results obtained at room temperature provide quantitative information on the position of the Fermi level for films with different oxygen contents. Systematic analysis of the measurements performed in the superconducting state indicate that the optical response associated with nonequilibrium properties of YBCO depends strongly on excitation intensity and sample thickness. The observed ultrafast refractive nonlinearity under the low laser excitation cannot be comprehensively interpreted as the relaxation dynamics of quasi-particles, and is speculated to be correlated to the existence of the nonequilibrium intermediate state.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ting Gong, Y. Kostoulas, Li Xing Zheng, W. Xiong, Witold Kula, Roman Sobolewski, and Philippe M. Fauchet "Femtosecond optical nonlinearities in YBa2Cu3O7-x", Proc. SPIE 1861, Ultrafast Pulse Generation and Spectroscopy, (17 June 1993); doi: 10.1117/12.147068; https://doi.org/10.1117/12.147068

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