Experimental Investigation of Ultrashort Pulse Laser-Induced Breakdown Thresholdsin Aqueous Media

摘要

Laser induced breakdown (LIB) thresholds are determined for pulse durations of2.4 ps, 400 fs, and 100 fs at 580 nm in high purity water, saline and tap water. The dependence of LIB 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 LIB, 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.