Ablation process of 1-kHz femtosecond lasers (pulse duration of 148 fs, wavelength of 775 nm) of Au film on silica substrates is studied. The thresholds for single and multi pulses can be obtained directly from the relation between the squared diameter D2 of the ablated craters and the laser fluence 'phi'0. From the plot of the accumulated laser fluence N'phi'_(th)(N) and the number of laser pulses N, incubation coefficient of Au film is obtained to be 0.765. Some experimental data obtained around the single pulse threshold are in good agreement with the theoretical calculation.
© 2005 Chinese Optics Letters
(140.3330) Lasers and laser optics : Laser damage
(160.3380) Materials : Laser materials
(260.3910) Physical optics : Metal optics
(310.3840) Thin films : Materials and process characterization
Xiaochang Ni, Ching-Yue Wang, Yinzhong Wu, Li Yang, Wei Jia, and Lu Chai, "Femtosecond laser ablation of Au film around single pulse threshold," Chin. Opt. Lett. 4, 225-227 (2006)