A first-order model for computation of laser-induced breakdown thresholds in condensed media

Paul K. Kennedy, Stephen A. Boppart, Daniel X. Hammer, Benjamin A. Rockwell, Gary D. Noojin, W. P. Roach

Research output: Contribution to journalConference articlepeer-review


An analytic, first-order model has been developed to calculate irradiance thresholds for laser-induced breakdown (LIB) in condensed media, including fluids and ocular media. The model is derived from the simple rate equation formalism of Shen for cascade breakdown in solids and from the theory of multiphoton ionization in condensed media developed by Keldysh. Analytic expressions have been obtained for the irradiance thresholds corresponding to multiphoton breakdown, to cascade breakdown, and to initiation of cascade breakdown by multiphoton ionization of seed electrons (multiphoton initiation threshold). The model has been incorporated into a computer code and code results compared to experimentally measured irradiance thresholds for breakdown of ocular media, saline, and water by nanosecond, picosecond, and femtosecond laser pulses in the visible and near-infrared. Theoretical values match experiment to within a factor of 2 or better, over a range of pulsewidths spanning five orders of magnitude, a reasonably good match for a first order model.

Original languageEnglish (US)
Pages (from-to)48-59
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - May 22 1995
Externally publishedYes
EventLaser-Tissue Interaction VI 1995 - San Jose, United States
Duration: Feb 1 1995Feb 8 1995


  • Laser-induced breakdown
  • Model
  • Ocular media
  • Thresholds
  • Water

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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