Ultrafast electron and material dynamics following femtosecond filamentation induced excitation of transparent solids

AbstractWe examine the spatiotemporal dynamics of filamentation and subsequent material changes in two transparent media, fused silica and poly(methyl methacrylate) (PMMA), using inline holographic microscopy. We are able to dynamically observe the nonlinear propagation of femtosecond laser pulses and the consequent evolution of the electronic excitatio n and trapping inside the bulk of both materials. In the case of fused silica we reveal the physical conditions for the formation of nanogratings, measuring excited electron densities well below the critical density while for PMMA we show that excited electrons with densities exceeding 1018 cm−3, exhibit complex trapping dynamics in a 200 fs time scale. The clear demonstration of ultrafast sub-ps photochemical processes that take place during the irradiation of PMMA with femtosecond pulses will have a strong impact on the laser microprocessing of polymers and nanosurgery applications of bio-related materials.

[1]  Walter Perrie,et al.  Photochemistry of refractive index structures in poly(methyl methacrylate) by femtosecond laser irradiation. , 2007, Optics letters.

[2]  H Lubatschowski,et al.  Computational model for nonlinear plasma formation in high NA micromachining of transparent materials and biological cells. , 2007, Optics express.

[3]  Stylianos Tzortzakis,et al.  In-line holography for the characterization of ultrafast laser filamentation in transparent media , 2008 .

[4]  E. Mazur,et al.  Dynamics of femtosecond laser-induced breakdown in water from femtoseconds to microseconds. , 2002, Optics express.

[5]  I Zergioti,et al.  Plasma strings from ultraviolet laser filaments drive permanent structural modifications in fused silica. , 2007, Optics letters.

[6]  B. Abel,et al.  The hydrated electron: a seemingly familiar chemical and biological transient. , 2011, Angewandte Chemie.

[7]  J. Ihlemann,et al.  Plasma effects in picosecond-femtosecond UV laser ablation of polymers , 2004 .

[8]  Kenji Fueki,et al.  Wavelength sensitivity of the photodegradation of poly(methyl methacrylate) , 1993 .

[9]  Guillaume Petite,et al.  Dynamics of femtosecond laser interactions with dielectrics , 2004 .

[10]  P. Meynadier,et al.  Subpicosecond study of carrier trapping dynamics in wide-band-gap crystals , 1997 .

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

[12]  Paolo Di Trapani,et al.  Time-resolved refractive index and absorption mapping of light-plasma filaments in water. , 2007, Optics letters.

[13]  E. Mazur,et al.  Femtosecond laser micromachining in transparent materials , 2008 .

[14]  Cyril Hnatovsky,et al.  Pulse duration dependence of femtosecond-laser-fabricated nanogratings in fused silica , 2005 .

[15]  A. Couairon,et al.  Femtosecond filamentation in transparent media , 2007 .

[16]  A. Couairon,et al.  Self-guided propagation of ultrashort IR laser pulses in fused silica. , 2001 .

[17]  D. Papazoglou,et al.  Physical mechanisms of fused silica restructuring and densification after femtosecond laser excitation [Invited] , 2011 .

[18]  P. Corkum,et al.  Optically produced arrays of planar nanostructures inside fused silica. , 2006, Physical review letters.

[19]  A. Vogel,et al.  Mechanisms of femtosecond laser nanosurgery of cells and tissues , 2005 .

[20]  M. Stuke,et al.  PHOTOFRAGMENTATION PATHWAYS OF A PMMA MODEL-COMPOUND UNDER UV EXCIMER LASER ABLATION CONDITIONS , 1990 .

[21]  L. M. Barker,et al.  Shock‐Wave Studies of PMMA, Fused Silica, and Sapphire , 1970 .

[22]  A. Vogel,et al.  Laser-induced plasma formation in water at nanosecond to femtosecond time scales: Calculation of thresholds, absorption coefficients, and energy density , 1999 .

[23]  P. Kazansky,et al.  Form birefringence and negative index change created by femtosecond direct writing in transparent materials. , 2004, Optics letters.

[24]  S. Naroo,et al.  Poly(methyl methacrylate) model study of optical surface quality after excimer laser photorefractive keratectomy , 2001, Journal of cataract and refractive surgery.

[25]  J. K. Thomas,et al.  Spectroscopic Investigation of Photoinduced Charge Separation and Recombination in Solid Polymers , 1998 .

[26]  Kazuyoshi Itoh,et al.  Filamentary cavity formation in poly(methyl methacrylate) by single femtosecond pulse , 2005 .

[27]  Walter Perrie,et al.  Pulse-duration dependency of femtosecond laser refractive index modification in poly(methyl methacrylate). , 2008, Optics letters.

[28]  Perry,et al.  Nanosecond-to-femtosecond laser-induced breakdown in dielectrics. , 1996, Physical review. B, Condensed matter.

[29]  Holger Lubatschowski,et al.  Streak formation as side effect of optical breakdown during processing the bulk of transparent Kerr media with ultra-short laser pulses , 2005 .

[30]  Saulius Juodkazis,et al.  Laser-matter interaction in the bulk of a transparent solid: confined microexplosion and void formation , 2006 .

[31]  P. Corkum,et al.  Memory in nonlinear ionization of transparent solids. , 2006, Physical review letters.

[32]  Y. Kivshar,et al.  Photonic bandgap properties of void-based body-centered-cubic photonic crystals in polymer. , 2005, Optics express.

[33]  D. Papazoglou,et al.  Four-dimensional visualization of single and multiple laser filaments using in-line holographic microscopy , 2011 .

[34]  Bernard Prade,et al.  Writing of permanent birefringent microlayers in bulk fused silica with femtosecond laser pulses , 1999 .

[35]  Andreas Kaiser,et al.  Microscopic processes in dielectrics under irradiation by subpicosecond laser pulses , 2000 .

[36]  Y. Shimotsuma,et al.  Self-organized nanogratings in glass irradiated by ultrashort light pulses. , 2003, Physical review letters.

[37]  Weijia Yang,et al.  Self-assembled periodic sub-wavelength structures by femtosecond laser direct writing. , 2006, Optics express.

[38]  Picosecond coherent Raman study of solid-state chemical reactions during laser polymer ablation , 1994 .

[39]  Albert Feldman,et al.  Optical and physical parameters of Plexiglas 55 and Lexan. , 1979, Applied optics.