Femtosecond laser ablation from sodium chloride and barium fluoride

The microscopic processes leading to material removal from sodium chloride (1 0 0) and barium fluoride (1 1 1) surfaces upon irradiation with near infrared femtosecond laser pulses are investigated using time-of-flight mass spectroscopy of charged particles. A pump-probe excitation setup permits us to follow the dynamic development of the charged particle emission on a femtosecond time scale. We find that the emission of electrons as well as of positive ions is mostly governed by the transient light intensity during the impact of the laser pulse. However, the correlation signal exhibits asymmetric shoulders, unexpectedly. (C) 2002 Elsevier Science B.V. All rights reserved.