title: Femtosecond laser-induced thermal lens effect in chromium film.
abstract: The thermal lens (TL) effect induced by femtosecond laser pulses in chromium film is reported. A Fresnel diffraction theory is used to explain the TL effect. The intensity profile of the TL calculated by the theoretical model is in agreement with the experimental results. The contrast ratio of the TL is defined to describe the TL effect, and we find that the maximum contrast ratio of the TL effect is obtained when the probe beam is recorded at a characteristic distance. The dependence of the contrast ratio of the TL on different pump laser power levels and delay times is also investigated. Numerical simulations are also consistent with the experimental results.
authors.affiliation: Laboratory of Information Optics and Opto-Electronic Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-216 Shanghai 201800, China.
authors.forename: Linwei
authors.initials: L
authors.lastname: Zhu
authors.forename: Changhe
authors.initials: C
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: Jia