Title :
Experimental investigation of ultrashort pulse laser-induced breakdown thresholds in aqueous media
Author :
Hammer, Daniel X. ; Thomas, Robert J. ; Noojin, Gary D. ; Rockwell, Benjamin A. ; Kennedy, Paul K. ; Roach, William P.
Author_Institution :
Armstrong Lab., Brooks Air Force Base, TX, USA
fDate :
4/1/1996 12:00:00 AM
Abstract :
Laser-induced breakdown (LIE) thresholds are determined for pulse durations of 2.4 ps, 400 fs, and 100 fs at 580 mn in high purity water, saline and tap water. The dependence of LIE irradiance thresholds on pulse duration, optical wavelength, and focal volume is examined, and the experimental data obtained is compared with a theoretical model. The slopes of the probability curves calculated are compared with mechanisms for LIE, namely avalanche ionization, multiphoton initiated avalanche ionization, and multiphoton ionization. Lastly, the dependence of the peak breakdown electric field on pulse duration and focal volume is empirically determined and compared with previous work
Keywords :
biological effects of laser radiation; electric breakdown; health hazards; high-speed optical techniques; laser beam effects; safety; 100 fs; 2.4 ps; 400 fs; 580 nm; aqueous media; avalanche ionization; focal volume; irradiance thresholds; multiphoton initiated avalanche ionization; multiphoton ionization; optical wavelength; peak breakdown electric field; probability curves; pulse duration; pulse durations; saline; tap water; ultrashort pulse laser-induced breakdown thresholds; water; Electric breakdown; Gas lasers; Ionization; Laboratories; Laser theory; Optical pulses; Plasmas; Pulse measurements; Radiation safety; Solids;
Journal_Title :
Quantum Electronics, IEEE Journal of
