EXCIMER-LASER INDUCED SURFACE MODIFICATIONS AND MATTER INTERACTION USING DOUBLE-PULSE-TECHNIQUE (DPT)

Excimer laser radiation is excellently absorbed by metallic and cerami c surfaces. However, under certain conditions the use of excimer laser s in materials processing may be limited by plasma formation, plasma r eflection and absorption mechanisms. This may restrict possible excime r laser applications to be carried out using certain beam sources (e.g . specified pulse duration or pulse energy) or beam qualities. The aim of the current investigations is to improve and to enhance the coupli ng efficiency by modifying the pulse length of the laser system. One p ossible method to change the pulse length and pulse energy very quickl y is to build up two externally triggered laser sources. The master ti ming system, developed at the ATZ-EVUS facilities is used to switch bo th lasers simultaneously. The pulse energy as well as the pulse length can be doubled using this system. Fundamental investigations have bee n carried out to determine the influence of the delay between the two laser pulses on the plasma formation, propagation and the plasma absor ption. The plasma absorption and the correspondent removal rates are c orrelated to the chosen delay value. First experimental results will b e given to demonstrate the potential of this technology especially for the excimer laser treatment of metals.