The development of new and more efficient schemes for improving the energy conversion from the optical radiation field into thermal, mechanical and or ionizational energy of target materials is a main concern in numerous laser effect studies, both in fundamental research and industrial applications. The present paper deals with recent investigations, carried out at ISL, by using a novel type of repetitively pulsed CO2-laser. Infrared pulse energies up to 150 J and repetition rates up to one hundred pulses per second provide powers up to 15 kW. Peak powers (close to 100 MW) are depending on pulse lengths, which can be set from about 2 to 10 microseconds. Experiments have been performed to study repetitively pulsed large area, 'out-of-band'-plasma supported processes, induced on optically transparent dielectric materials. Further so-called 'in-band'-studies of semiconductor materials were carried out, by using a frequency doubled Nd-YAG-laser and a dye-laser. Due to the small spot approach, experiments could be performed with rather small pulse energies of 500 to 600 mJ to yield fluences up to several tens of J/cm2. Examples, both concerning the high energy, (out-of-band) and the lower energy (in-band) measurements will be discussed for various types of targets. Mechanisms involved include quasi-explosive thermal ablation and absorption-wave supported impulsive loading due to thermo- mechanical processes.