Femtosecond dynamics of dielectric films in the pre-ablation regime

The ultra-fast dynamics of dielectric oxide materials excited close to the laser-damage threshold is studied by performing transient reflection and transmission pump–probe measurements on TiO2, Ta2O5, and HfO2 films. The time-dependent dielectric constant is retrieved taking into account standing-wave effects of both pump and probe. A sub-100-fs transient is followed by a 1-ps transient, during which a sign reversal from negative to positive is observed in the real part of the induced change in the dielectric function, indicating the formation of deep defect states, possibly self-trapped excitons.

[1]  G. Jellison,et al.  Parameterization of the optical functions of amorphous materials in the interband region , 1996 .

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

[3]  Brent C. Stuart,et al.  Ultrashort-pulse laser machining of dielectric materials , 1999 .

[4]  G. Mourou,et al.  A study of the deterministic character of optical damage by femtosecond laser pulses and applications to nanomachining , 2003 .

[5]  R. Kalia,et al.  Universal behavior of exchange-correlation energy in electron-hole liquid , 1982 .

[6]  G. Mourou,et al.  Femtosecond Optical Breakdown in Dielectrics , 1998 .

[7]  Arnold,et al.  Acoustic-phonon runaway and impact ionization by hot electrons in silicon dioxide. , 1992, Physical review. B, Condensed matter.

[8]  Klaus Sokolowski-Tinten,et al.  Generation of dense electron-hole plasmas in silicon , 2000 .

[9]  Pierre Meynadier,et al.  Time-resolved study of laser-induced colour centres in ? , 1996 .

[10]  D T Wei,et al.  Ion beam interference coating for ultralow optical loss. , 1989, Applied optics.

[11]  O. Apel,et al.  Nonlinear absorption of thin Al2O3 films at 193 nm. , 2000, Applied optics.

[12]  Kai Starke,et al.  Femtosecond laser pulse induced breakdown in dielectric thin films , 2001 .

[13]  Gerald Earle Jellison,et al.  Erratum: ‘‘Parameterization of the optical functions of amorphous materials in the interband region’’ [Appl. Phys. Lett. 69, 371 (1996)] , 1996 .

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

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

[16]  J. Jasapara,et al.  Retrieval of the dielectric function of thin films from femtosecond pump-probe experiments , 2002 .

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

[18]  Razvan Stoian,et al.  Ultrashort-laser-pulse damage threshold of transparent materials and the role of incubation , 1999 .

[19]  J. Krüger,et al.  Surface damage and color centers generated by femtosecond pulses in borosilicate glass and silica , 2004 .

[20]  Gerard Mourou,et al.  SHORT-PULSE LASER DAMAGE IN TRANSPARENT MATERIALS AS A FUNCTION OF PULSE DURATION , 1999 .

[21]  P. Young.  dc electrical conduction in thin Ta2O5 films. II. Highly imperfect films , 1976 .

[22]  F. Krausz,et al.  Precision laser ablation of dielectrics in the 10-fs regime , 1999 .

[23]  Noriaki Itoh,et al.  Optical studies of self-trapped excitons in SiO2 , 1988 .

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