To find the best parameters for our LMS instrument regarding laser beam characterstics, e.g. puls lenght, wavelenght, repetion rate, laser irradiance on the sample, different kind of lasers with their own charactersitics has to be investigated in detail. In the following a short overview of lasers which we are testing at the moment and in the near future.
Nanosecond laser system
At the moment we are using a Nd:YAG laser system is in the UV range. The wavlenght is hereby 266nm, ~3.5ns puls lenght, 20Hz repetition rate and up to 170GW/cm2 on the sample is achievable. However this is much more than we actually need for our pourpose. Allready 10 GW/cm2 is sufficient for stable ablation condition on the sample.
Femtosecond laser system
After measurement campaigns using th nanosecond laser system our group will go on with a femtosecond laser system. The system has hereby the following characteristics: 150 fs puls lenght, 1kHz repetition rate, wavelenght of 755nm and far enough power. Using additional modules for this systems we will be able to go down to wavelenghts of ~260nm and up to the far infrared, ~3000nm. Furthermore, the puls lenghts are also adjustable into the range of pico seconds!