Universal threshold for femtosecond laser ablation with oblique illumination

Xiao-Long Liu, Weibo Cheng, Massimo Petrarca, Pavel Polynkin
2016 Applied Physics Letters  
We quantify the dependence of the single-shot ablation threshold on the angle of incidence and polarization of a femtosecond laser beam, for three dissimilar solid-state materials: a metal, a dielectric and a semiconductor. Using the constant, linear value of the index of refraction, we calculate the laser fluence transmitted through the air-material interface at the point of ablation threshold. We show that, in spite of the highly nonlinear ionization dynamics involved in the ablation process,
more » ... the so defined transmitted threshold fluence is universally independent of the angle of incidence and polarization of the laser beam for all three material types. We suggest that angular dependence of ablation threshold can be utilized for profiling fluence distributions in ultra-intense femtosecond laser beams.
doi:10.1063/1.4965850 fatcat:qnmhyp6imrbofgerat52bxbcgy