In situ observation of photoinduced refractive-index changes in filaments formed in glasses by femtosecond laser pulses.

We investigated the relationship between the formation of filaments and local refractive-index changes induced by femtosecond laser pulses in silica glass. In situ observation revealed that the location of a filament coincided with that of the refractive-index change. Observation also showed that the region of refractive-index change was elongated toward the upstream direction of the laser pulses with increasing exposure time. The region of refractive-index change was several hundred micrometers long, and its diameter was smaller than 2 mum. The refractive-index change was confirmed by two of three different methods to be as large as 0.8 x 10(-2).

[1]  Kazuyoshi Itoh,et al.  Estimation of the Refractive Index Change in Glass Induced by Femtosecond Laser Pulses , 2000 .

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

[3]  Hiroaki Misawa,et al.  Microfabrication and Characteristics of Two-Dimensional Photonic Crystal Structures in Vitreous Silica , 1999 .

[4]  A. Gaeta,et al.  Infrared photosensitivity in silica glasses exposed to femtosecond laser pulses. , 1999, Optics letters.

[5]  Minoru Obara,et al.  Observation of Self-Channeled Plasma Formation and Bulk Modification in Optical Fibers Using High-Intensity Femtosecond Laser , 1998, Technical Digest. 1998 EQEC. European Quantum Electronics Conference (Cat. No.98TH8326).

[6]  David Ashkenasi,et al.  Application of self-focusing of ps laser pulses for three-dimensional microstructuring of transparent materials , 1998 .

[7]  Tsuneo Mitsuyu,et al.  Three-Dimensional Microscopic Crystallization in Photosensitive Glass by Femtosecond Laser Pulses at Nonresonant Wavelength , 1998 .

[8]  K Miura,et al.  Writing Waveguides and Gratings in Silica and Related Materials by Femto-Second Laser , 1998, Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides: Applications and Fundamentals.

[9]  Tsuneo Mitsuyu,et al.  Photowritten optical waveguides in various glasses with ultrashort pulse laser , 1997 .

[10]  J. P. Callan,et al.  Three-dimensional optical storage inside transparent materials. , 1996, Optics letters.

[11]  K. Miura,et al.  Writing waveguides in glass with a femtosecond laser. , 1996, Optics letters.

[12]  Gerard Mourou,et al.  Laser‐induced breakdown by impact ionization in SiO2 with pulse widths from 7 ns to 150 fs , 1994 .

[13]  G. Steinberg,et al.  Filamentary Tracks Formed in Transparent Optical Glass by Laser Beam Self-Focusing. I. Experimental Investigation , 1971 .