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Time‐resolved observations of shock waves and cavitation bubbles generated by femtosecond laser pulses in corneal tissue and water
Author(s) -
Juhasz Tibor,
Kastis George A.,
Suárez Carlos,
Bor Zsolt,
Bron Walter E.
Publication year - 1996
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/(sici)1096-9101(1996)19:1<23::aid-lsm4>3.0.co;2-s
Subject(s) - femtosecond , cavitation , laser , shock wave , materials science , nanosecond , picosecond , optics , shock (circulatory) , bubble , wavelength , optoelectronics , physics , acoustics , medicine , mechanics , thermodynamics
Background and Objective Photodisruption in ocular media with high power pulsed lasers working at non‐absorbing frequencies have become a well established surgical tool since the late seventies. Shock waves and cavitation bubbles generated by the optical breakdown may strongly influence the surgical effect of photodisruptive lasers. We have investigated the shock wave and cavitation bubble effects of femtosecond laser pulses generated during photodisruption in corneal tissue and water. The results are compared to those obtained with longer laser pulses. Study Design/Materials and Methods Laser pulses with 150 fs duration at ∼620 nm wavelength have been focused into corneal tissue and water to create optical breakdown. Time‐resolved flash photography has been used to investigate the dynamics of the generated shock waves and cavitation bubbles. Results A rapid decay of the shock waves is observed in both materials with similar temporal characteristics and with a spatial range considerably smaller than that of shock waves induced by picosecond (or nanosecond) optical breakdown. Cavitation bubbles are observed to develop more rapidly and to reach smaller maximum diameter than those generated by longer pulses. In corneal tissue, single intrastromal cavitation bubbles generated by femtosecond pulses disappear within a few tens of seconds, notably faster than cavitation bubbles generated by picosecond pulses. Conclusions The reduced shock wave and cavitation bubble effects of the femtosecond laser result in more localized tissue damage. Therefore, a more confined surgical effect should be expected from a femtosecond laser than that from picosecond (or nanosecond) lasers. This indicates a potential benefit from the applications of femtosecond laser technology to intraocular microsurgery. © 1996 Wiley‐Liss, Inc.