title: Generation and elimination of polarization-dependent ablation of cubic crystals by femtosecond laser radiation.
abstract: We experimentally showed that the π/2-period oscillation of an ablation area with laser polarization direction can be observed in GaAs, ZnSe, MgO and LiF with cubic crystal by a femtosecond laser (800 nm, 100 fs) and that the modulation in the ablation area can be controlled by the laser fluence. While the polarization dependence is sustained in a wide range of laser fluences for a narrow band-gap crystal, it is strongly suppressed with a slight augmentation of laser fluence in a wide band-gap material. The polarization-dependent ablation is explained by the crystal's orientation-dependent reduced-electron mass and the resultant contrasting nonlinear absorptions with slightly different reduced electron mass. The interplay between photoionization and avalanche ionization is discussed to interpret the influence of laser fluence on polarization-dependent ablation. Based on Keldysh's theory, polarization-dependent ablation occurs in a mixed regime between tunneling and multiphoton ionization.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Wenlong
authors.initials: W
authors.lastname: Rong
authors.forename: Lan
authors.initials: L
authors.lastname: Jiang
authors.forename: Kaihu
authors.initials: K
authors.lastname: Zhang
authors.forename: Cong
authors.initials: C
authors.lastname: Li
authors.forename: Qiang
authors.initials: Q
authors.lastname: Cao
authors.forename: Guangming
authors.initials: G
authors.lastname: Zhang
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Lu
mesh_terms: D003460:Crystallization; D007834:Lasers; D008027:Light; D008855:Microscopy, Electron, Scanning; D055620:Optical Phenomena; D011827:Radiation; D013997:Time Factors