TY - JOUR
T1 - A first-order model for computation of laser-induced breakdown thresholds in condensed media
AU - Kennedy, Paul K.
AU - Boppart, Stephen A.
AU - Hammer, Daniel X.
AU - Rockwell, Benjamin A.
AU - Noojin, Gary D.
AU - Roach, W. P.
N1 - Funding Information:
This work was supported by Armstrong Laboratory and by the Air Force Office of Scientific Research (AFOSR), Grant-2312A101. The authors would like to thank Dr. Alfred Vogel for valuable discussions on short pulse LIB in aqueous media.
Publisher Copyright:
© 1995 SPIE. All rights reserved.
PY - 1995/5/22
Y1 - 1995/5/22
N2 - 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.
AB - 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.
KW - Laser-induced breakdown
KW - Model
KW - Ocular media
KW - Thresholds
KW - Water
UR - http://www.scopus.com/inward/record.url?scp=85076676814&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85076676814&partnerID=8YFLogxK
U2 - 10.1117/12.209922
DO - 10.1117/12.209922
M3 - Conference article
AN - SCOPUS:85076676814
SN - 0277-786X
VL - 2391
SP - 48
EP - 59
JO - Proceedings of SPIE - The International Society for Optical Engineering
JF - Proceedings of SPIE - The International Society for Optical Engineering
T2 - Laser-Tissue Interaction VI 1995
Y2 - 1 February 1995 through 8 February 1995
ER -