In this paper we present experimental results on the behaviour of light supercontinuum generation and filamentation when ultrafast laser induced material modifications are accumulating in fused silica. We show that due to material modification supercontinuum spectrum starts to shrink and its intensity rapidly decreases; this rate is highly affected by the laser pulse repetition rate. The filament tends to split along the beam propagating path resulting in inhomogeneous distribution of the modified material.
Keywords: femtosecond micromachining, the material modification, filamentation, supercontinuum
PACS: 42.62.Cf, 42.65.Sf, 42.70.Ce

ŠVIESOS GIJŲ FORMAVIMAS IR SUPERKONTINUUMO GENERAVIMAS FEMTOSEKUNDINIAIS LAZERIO IMPULSAIS MODIFIKUOTAME KVARCINIAME STIKLE
D. Paipulas, A. Balskienė, V. Sirutkaitis
Vilniaus universiteto Fizikos fakulteto Kvantinės elektronikos katedra, Vilnius, Lietuva

Pateikiami eksperimentiniai rezultatai, gauti tiriant lazeriu modifikuotų darinių poveikį netiesiniams reiškiniams, vykstantiems lydyto kvarco stikle. Parodoma, kad dėl modifikacijų didelio pasikartojimo dažnio impulsais kuriamas superkontinuumas sparčiai silpsta, vyksta spektro siaurėjimas ir trumpabangio krašto slinkimas link ilgesniųjų bangų. Parodoma, kad šviesos gija lydytame kvarce skyla išilgai pluošto sklidimo krypties, o šis skilimas lemia nevienalyčius modifikuotos medžiagos darinius.

References / Nuorodos

[1] K.M. Davis, K. Miura, N. Sugimoto, and K. Hirao, Writing waveguides in glass with a femtosecond laser, Opt. Lett. 21(21), 1729–1731 (1996),
http://dx.doi.org/10.1364/OL.21.001729
[2] Femtosecond Laser Micromachining: Photonic and Microfluidic Devices in Transparent Materials, eds. R. Osellame, G. Cerullo, and R. Ramponi (Springer, 2012),
http://www.springer.com/physics/optics+%26+lasers/book/978-3-642-23365-4
[3] A. Couairon and A. Mysyrowicz, Fermtosecond filamentation in transparent media, Phys. Rep. 441(2–4), 47–189 (2007),
http://dx.doi.org/10.1016/j.physrep.2006.12.005
[4] S.L. Chin, Femtosecond Laser Filamentation (Springer, 2010),
http://dx.doi.org/10.1007/978-1-4419-0688-5
[5] L. Sudrie, A. Couairon, M. Franco, B. Lamouroux, B. Prade, S. Tzortzakis, and A. Mysyrowicz, Femtosecond laser-induced damage and filamentary propagation in fused silica, Phys. Rev. Lett. 89 (18), 186601 (2002),
http://dx.doi.org/10.1103/PhysRevLett.89.186601
[6] N.T. Nguyen, A. Saliminia, W. Liu, S.L. Chin, and R. Vallée, Optical breakdown versus filamentation in fused silica by use of femtosecond infrared laser pulses, Opt. Lett. 28(17), 1591–1593 (2003),
http://dx.doi.org/10.1364/OL.28.001591
[7] W. Watanabe, T. Tamaki, and K. Itoh, Filamentation in laser microprocessing and microwelding, Proc. SPIE 6733 , 67332F (2007),
http://dx.doi.org/10.1117/12.753150
[8] E.O. Smetanina, A.E. Dormidonov, and V.P. Kandidov, Supercontinuum generation in filamentation of femtosecond laser pulse in fused silica, Proc. SPIE 8159, 81590L (2011),
http://dx.doi.org/10.1117/12.893108
[9] D.V. Skryabin and A.V. Gorbach, Colloquium: Looking at a soliton through the prism of optical supercontinuum, Rev. Mod. Phys 82, 1287–1299 (2010),
http://dx.doi.org/10.1103/RevModPhys.82.1287
[10] D. Faccio, A. Averchi, A. Lotti, M. Kolesik, J.V. Moloney, A. Couairon, and P. Di Trapani, Generation and control of extreme blueshifted continuum peaks in optical Kerr media, Phys. Rev. A 78(3), 033825 (2008),
http://dx.doi.org/10.1103/PhysRevA.78.033825
[11] P. Martin, S. Guizard, Ph. Daguzan, G. Petite, P. D’Oliveira, P. Meynadier, and M. Perdrix, Subpicosecond study of carrier trapping dynamics in wide-band-gap crystals. Phys. Rev. B 55(9), 5799–5810 (1997),
http://dx.doi.org/10.1103/PhysRevB.55.5799
[12] C. Itoh, K. Tanimura, and N. Itoh, Optical studies of self-trapped excitons in SiO₂, J. Phys. C Solid State Phys. 21(26), 4693–4702 (1988),
http://dx.doi.org/10.1088/0022-3719/21/26/017
[13] J.W. Chan, T.R. Huser, S.H. Risbud, and D.M. Krol, Modification of the fused silica glass network associated with waveguide fabrication using femtosecond laser pulses, Appl. Phys. A 76, 367–372 (2003),
http://dx.doi.org/10.1007/s00339-002-1822-9
[14] D. Blömer, A. Szameit, F. Dreisow, T. Schreiber, S. Nolte, and A. Tünnermann, Nonlinear refractive index of fs-laser-written waveguides in fused silica, Opt. Express 14(6), 2151–2157 (2006),
http://dx.doi.org/10.1364/OE.14.002151
[15] S.L. Chin, A. Brodeur, S. Petit, O.G. Kosareva, and V.P. Kandidov, Filamentation and supercontinuum generation during the propagation of powerful ultrashort laser pulses in optical media (white light  laser), J. Nonlinear Opt. Phys. Mater. 8(1), 121–146 (1999),
http://dx.doi.org/10.1142/S0218863599000096
[16] A. Dubietis, E. Kučinskas, G. Tamošauskas, E. Gaižauskas, M.A. Porras, and P.D. Trapani, Self-reconstruction of light filaments, Opt. Lett. 29(24), 2893–2895 (2004),
http://dx.doi.org/10.1364/OL.29.002893
[17] V. Sirutkaitis, E. Gaizauskas, V. Kudriashov, M. Barkauskas, V. Vaicaitis, R. Grigonis, and A.S. Piskarskas, Self-guiding supercontinuum generation and damage in bulk materials induced by femtosecond pulses, Proc. SPIE 4932, 346–357 (2003),
http://dx.doi.org/10.1117/12.472427
[18] I. Zergioti, K.D. Kyrkis, D.G. Papazoglou, and S. Tzortzakis, Structural modifications in fused silica induced by ultraviolet fs laser filaments, Appl. Surf. Sci. 253(19), 7865–7868 (2007),
http://dx.doi.org/10.1016/j.apsusc.2007.02.095
[19] M. Bernier, S. Gagnon, and R. Vallée, Role of the 1D optical filamentation process in the writing of first order fiber Bragg gratings with femtosecond pulses at 800 nm [Invited], Opt. Mater. Express 1(5), 832–844 (2011),
http://dx.doi.org/10.1364/OME.1.000832