Damage formation on fused silica illuminated with ultraviolet-infrared femtosecond pulse pairs

We investigate damage formation on the surface of fused silica by two femtosecond laser pulses, a tightly focused 266 nm (UV) pulse followed by a loosely focused 800 nm (IR) pulse. We show that the damage size is determined by the UV pulse, and only a small fraction of the normal UV damage threshold energy is needed to cause damage when combined with the properly delayed IR pulse. Our results, analyzed with a rate equation model, suggest that the UV pulse generates seed electrons through multiphoton absorption and the IR pulse utilizes these electrons to cause damage by avalanche ionization. By tuning such parameters like pulse energy, time delay, IR pulse duration and polarization, we further demonstrate that damage profile can be controlled.

[1]  Iu. P. Raizer.  Laser-induced discharge phenomena , 1977 .

[2]  Cheng-Hsiang Lin,et al.  Investigations of femtosecond-nanosecond dual-beam laser ablation of dielectrics. , 2010, Optics letters.

[3]  Jan Siegel,et al.  Plasma formation and structural modification below the visible ablation threshold in fused silica upon femtosecond laser irradiation , 2007 .

[4]  J. Liu.  Simple technique for measurements of pulsed Gaussian-beam spot sizes. , 1982, Optics letters.

[5]  P Balling,et al.  Femtosecond-laser ablation dynamics of dielectrics: basics and applications for thin films , 2013, Reports on progress in physics. Physical Society.

[6]  V. Apalkov,et al.  Controlling dielectrics with the electric field of light , 2012, Nature.

[7]  A. Couairon,et al.  Femtosecond laser-induced damage and filamentary propagation in fused silica. , 2002, Physical review letters.

[8]  Koji Sugioka,et al.  VUV-UV multiwavelength excitation process for high-quality ablation of fused silica , 2013, Europe Optics + Optoelectronics.

[9]  P. Corkum,et al.  Femtosecond laser nanomachining initiated by ultraviolet multiphoton ionization. , 2013, Optics express.

[10]  G. Gibson,et al.  ULTRAFAST ELECTRON DYNAMICS IN FEMTOSECOND OPTICAL BREAKDOWN OF DIELECTRICS , 1999 .

[11]  Anatoly Zayats,et al.  Point-by-point inscription of 250-nm-period structure in bulk fused silica by tightly-focused femtosecond UV pulses: experiment and numerical modeling , 2010 .

[12]  P. Corkum,et al.  Control of energy deposition in femtosecond laser dielectric interactions , 2013 .

[13]  P. Corkum,et al.  Fabricating nanostructures on fused silica using femtosecond infrared pulses combined with sub-nanojoule ultraviolet pulses. , 2014, Optics letters.

[14]  G. Reider,et al.  Enhancement of laser ablation yield by two color excitation , 2005 .

[15]  David Grojo,et al.  Exciton-seeded multiphoton ionization in bulk SiO 2 , 2010 .

[16]  Eric Mazur,et al.  Laser-induced breakdown and damage in bulk transparent materials induced by tightly focused femtosecond laser pulses , 2001 .

[17]  P. Simon,et al.  Efficient submicron processing of metals with femtosecond UV pulses , 2003 .

[18]  Zhizhan Xu,et al.  Ultraviolet-infrared femtosecond laser-induced damage in fused silica and CaF2 crystals , 2006 .

[19]  Eric Mazur,et al.  Femtosecond laser micromachining in transparent materials , 2008 .

[20]  P. Corkum,et al.  Near-infrared femtosecond laser machining initiated by ultraviolet multiphoton ionization , 2013 .

[21]  E. Gamaly.  The physics of ultra-short laser interaction with solids at non-relativistic intensities , 2011 .

[22]  H. A. Schwettman,et al.  Midinfrared optical breakdown in transparent dielectrics. , 2003, Physical review letters.

[23]  Xianfan Xu,et al.  Ultrafast two-color ablation of fused silica , 2006 .