Studies of Laser Ablation of Liquid Water Under Conditions of Impulsive Heat Deposition Through Vibrational Excitations (IHDVE)

• Main Author: Franjic, Kresimir
• Other Authors: Miller, R. J. Dwayne
• Language: en_ca
• Published: 2010
• Subjects: laser surgery; mass spectrometry; 0752; 0760
• Online Access: http://hdl.handle.net/1807/24751

A new laser ablation mechanism of liquid water based on recent insights into its hydrogen bond dynamics has been studied and several applications of the ablation demonstrated. The mechanism, termed as Impulsive Heat Deposition through Vibrational Excitations (IHDVE), is based on the ability of the hydrogen bond network of water to rapidly thermalize vibrational O-H stretch excitations on a time scale of several picoseconds even for excitation intensities that are large enough to bring excited volumes far into the supercritical region. In this way, by using vibrationally resonant picosecond infrared laser pulses with sufficient energy, it is possible to drive ultrafast phase transitions in the excited water volume leading to a rapid and efficient ablation process of water and water rich targets with minimum perturbation of solute molecules of interest. The physics behind the IHDVE ablation process is outlined and the benefits of the IHDVE ablation are demonstrated for two important applications of tissue cutting and mass spectrometry of biomolecules. Finally, the development of two high power infrared laser systems suitable for the practical implementation of IHDVE is presented.