Analysis of the effects of spherical aberration on ultrafast laser-induced refractive index variation in glass.

We propose a comprehensive analysis of the effects that spherical aberration may have on the process of ultrafast laser photowriting in bulk transparent materials and discuss the consequences for the generated refractive index changes. Practical aspects for a longitudinal photowriting configuration are emphasized. Laser-induced index variation in BK7 optical glass and fused silica (a-SiO(2)) affected by spherical aberration are characterized experimentally using phase-contrast optical microscopy. Experimental data are matched by analytical equations describing light propagation through dielectric interfaces. Corrective solutions are proposed with a particular focus on the spatial resolution achievable and on the conditions to obtain homogeneously photo-induced waveguides in a longitudinal writing configuration.

[1]  J G Fujimoto,et al.  Photonic device fabrication in glass by use of nonlinear materials processing with a femtosecond laser oscillator. , 2001, Optics letters.

[2]  Shuhei Tanaka,et al.  Fabrication of high-efficiency diffraction gratings in glass. , 2005, Optics letters.

[3]  Saulius Juodkazis,et al.  Application of femtosecond laser pulses for microfabrication of transparent media , 2002 .

[4]  A. Tünnermann,et al.  Femtosecond, picosecond and nanosecond laser ablation of solids , 1996 .

[5]  Qihuang Gong,et al.  The refocusing behaviour of a focused femtosecond laser pulse in fused silica , 2003 .

[6]  P. Corkum,et al.  High-resolution study of photoinduced modification in fused silica produced by a tightly focused femtosecond laser beam in the presence of aberrations , 2005 .

[7]  T. Visser,et al.  ANNULAR FOCUSING THROUGH A DIELECTRIC INTERFACE : SCANNING AND CONFINING THE INTENSITY , 1998 .

[8]  Yoshimasa Kawata,et al.  Predictive aberration correction for multilayer optical data storage , 2006 .

[9]  Razvan Stoian,et al.  Direct Observation of Femtosecond Laser Induced Modifications in the Bulk of Fused Silica by Phase Contrast Microscopy , 2006 .

[10]  N. Huot,et al.  2D calculations of the thermal effects due to femtosecond laser-metal interaction , 2005 .

[11]  Steven M. Yalisove,et al.  Femtosecond pulsed laser direct write production of nano- and microfluidic channels , 2006 .

[12]  Peter Varga,et al.  Analytical solution of the diffraction integrals and interpretation of wave-front distortion when light is focused through a planar interface between materials of mismatched refractive indices , 1995 .

[13]  E. Mazur,et al.  Micromachining bulk glass by use of femtosecond laser pulses with nanojoule energy. , 2001, Optics letters.

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

[15]  T. S. Ong,et al.  Femtosecond laser application for high capacity optical data storage , 2004 .

[16]  Amir H Nejadmalayeri,et al.  Type II high-strength Bragg grating waveguides photowritten with ultrashort laser pulses. , 2007, Optics express.

[17]  Bernard Prade,et al.  Study of damage in fused silica induced by ultra-short IR laser pulses , 2001 .

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

[19]  Yan Li,et al.  Influence of focusing depth on the microfabrication of waveguides inside silica glass by femtosecond laser direct writing , 2006 .

[20]  Razvan Stoian,et al.  Spatial distribution of refractive index variations induced in bulk fused silica by single ultrashort and short laser pulses , 2007 .

[21]  T. Wilson,et al.  Aberration correction for confocal imaging in refractive‐index‐mismatched media , 1998 .