Theory and simulation on the threshold of water breakdown induced by focused ultrashort laser pulses

A comprehensive model is developed for focused pulse propagation in water. The model incorporates self-focusing, group velocity dispersion, and laser-induced breakdown in which an electron plasma is generated via cascade and multiphoton ionization processes. The laser-induced breakdown is studied first without considering self-focusing to give a breakdown threshold of the light intensity, which compares favorably with existing experimental results. The simple study also yields the threshold dependence on pulse duration and input spot size, thus providing a framework to view the results of numerical simulations of the full model. The simulations establish the breakdown threshold in input power and reveal qualitatively different behavior for picoand femto-second pulses. For longer pulses, the cascade process provides the breakdown mechanism, while for shorter pulses the cooperation between the self-focusing and the multiphoton plasma generation dominates the breakdown threshold.

[1]  D. Hammer,et al.  A first-order model for computation of laser-induced breakdown thresholds in ocular and aqueous media. II. Comparison to experiment , 1995 .

[2]  Jerome V Moloney,et al.  The effects of normal dispersion on collapse events , 1994 .

[3]  M. Feit,et al.  Effect of refraction on spot-size dependence of laser-induced breakdown , 1974 .

[4]  J. Rothenberg,et al.  Space - time focusing: breakdown of the slowly varying envelope approximation in the self-focusing of femtosecond pulses. , 1992, Optics letters.

[5]  Perry,et al.  Laser-induced damage in dielectrics with nanosecond to subpicosecond pulses. , 1995, Physical review letters.

[6]  Jerome V Moloney,et al.  Beam collapse as an explanation for anomalous ocular damage , 1993 .

[7]  Donna Strickland,et al.  Short pulse self-focusing , 1991, Photonics West - Lasers and Applications in Science and Engineering.

[8]  Peter A. Barnes,et al.  LASER INDUCED UNDERWATER SPARKS , 1968 .

[9]  J. Rothenberg.  Pulse splitting during self-focusing in normally dispersive media. , 1992, Optics letters.

[10]  Carmen A. Puliafito,et al.  Short-pulsed Nd:YAG laser microsurgery of the eye: Biophysical considerations , 1984 .

[11]  Benjamin A. Rockwell,et al.  Shielding effectiveness of femtosecond laser-induced plasmas in ultrapure water , 1993, Photonics West - Lasers and Applications in Science and Engineering.

[12]  V. Petrov,et al.  Self-focusing of light pulses in the presence of normal group-velocity dispersion. , 1992, Optics letters.

[13]  E. Yablonovitch,et al.  Avalanche Ionization and the Limiting Diameter of Filaments Induced by Light Pulses in Transparent Media , 1972 .

[14]  James G. Fujimoto,et al.  Time-resolved measurements of picosecond optical breakdown , 1989 .

[15]  Nicolaas Bloembergen,et al.  Superbroadening in H2O and D2O by self-focused picosecond pulses from a YAlG:Nd laser , 1977 .

[16]  Q. X. Li,et al.  Enhancement of ultrafast supercontinuum generation in water by the addition of Zn(2+) and K(+) cations. , 1987, Optics letters.

[17]  A. Newell,et al.  Self-focusing threshold in normally dispersive media. , 1994, Optics letters.

[18]  J. R. Morris,et al.  Time-dependent propagation of high energy laser beams through the atmosphere , 1976 .

[19]  Alfons Penzkofer,et al.  Stimulated Short-Wave Radiation due to Single-Frequency Resonances of χ (3) , 1973 .

[20]  P. Kennedy.  A first-order model for computation of laser-induced breakdown thresholds in ocular and aqueous media. I. Theory , 1995 .

[21]  James G. Fujimoto,et al.  Femtosecond laser-tissue interactions: Retinal injury studies , 1987 .

[22]  Yaochun Shen.  Principles of nonlinear optics , 1984 .

[23]  L. Keldysh,et al.  IONIZATION IN THE FIELD OF A STRONG ELECTROMAGNETIC WAVE , 1964 .

[24]  Gary D. Noojin,et al.  Experimental investigation of ultrashort pulse laser-induced breakdown thresholds in aqueous media , 1996 .

[25]  F. Docchio,et al.  Lifetimes of Plasmas Induced in Liquids and Ocular Media by Single Nd:YAG Laser Pulses of Different Duration , 1988 .

[26]  E. F. Maher,et al.  Transmission and Absorption Coefficients for Ocular Media of the Rhesus Monkey , 1978 .

[27]  B A Rockwell,et al.  Nonlinear refraction in vitreous humor. , 1993, Optics letters.

[28]  C. Sacchi.  Laser-induced electric breakdown in water , 1991 .