TY - GEN

T1 - Numerical calculation of nonlinear ultrashort laser pulse propagation in transparent Kerr media

AU - Arnold, C. L.

AU - Heisterkamp, A.

AU - Ertmer, W.

AU - Lubatschowski, H.

PY - 2005/3/21

Y1 - 2005/3/21

N2 - In the focal region of tightly focused ultrashort laser pulses, sufficient high intensities to initialize nonlinear ionization processes are easily achieved. Due to these nonlinear ionization processes, mainly multiphoton ionization and cascade ionization, free electrons are generated in the focus resulting in optical breakdown. A model including both nonlinear pulse propagation and plasma generation is used to calculate numerically the interaction of ultrashort pulses with their self-induced plasma in the vicinity of the focus. The model is based on a (3+1)-dimensional nonlinear Schrödinger equation describing the pulse propagation coupled to a system of rate equations covering the generation of free electrons. It is applicable to any transparent Kerr medium, whose linear and nonlinear optical parameters are known. Numerical calculations based on this model are used to understand nonlinear side effects, such as streak formation, occurring in addition to optical breakdown during short pulse refractive eye surgeries like fs-LASIK. Since the optical parameters of water are a good first-order approximation to those of corneal tissue, water is used as model substance. The free electron density distribution induced by focused ultrashort pulses as well as the pulses spatio-temporal behavior are studied in the low-power regime around the critical power for self-focusing.

AB - In the focal region of tightly focused ultrashort laser pulses, sufficient high intensities to initialize nonlinear ionization processes are easily achieved. Due to these nonlinear ionization processes, mainly multiphoton ionization and cascade ionization, free electrons are generated in the focus resulting in optical breakdown. A model including both nonlinear pulse propagation and plasma generation is used to calculate numerically the interaction of ultrashort pulses with their self-induced plasma in the vicinity of the focus. The model is based on a (3+1)-dimensional nonlinear Schrödinger equation describing the pulse propagation coupled to a system of rate equations covering the generation of free electrons. It is applicable to any transparent Kerr medium, whose linear and nonlinear optical parameters are known. Numerical calculations based on this model are used to understand nonlinear side effects, such as streak formation, occurring in addition to optical breakdown during short pulse refractive eye surgeries like fs-LASIK. Since the optical parameters of water are a good first-order approximation to those of corneal tissue, water is used as model substance. The free electron density distribution induced by focused ultrashort pulses as well as the pulses spatio-temporal behavior are studied in the low-power regime around the critical power for self-focusing.

KW - Nonlinear Pulse Propagation

KW - Ophthalmology

KW - Optical Breakdown

KW - Ultrashort Laser Pulses

UR - http://www.scopus.com/inward/record.url?scp=21844455756&partnerID=8YFLogxK

U2 - 10.1117/12.588903

DO - 10.1117/12.588903

M3 - Conference contribution

AN - SCOPUS:21844455756

T3 - Proceedings of SPIE - The International Society for Optical Engineering

SP - 126

EP - 137

BT - Commercial and Biomedical Applications of Ultrafast Lasers V

PB - SPIE

T2 - Lasers and Applications in Science and Engineering

Y2 - 22 January 2005 through 27 January 2005

ER -