Laser damage threshold of MgF2 thin films by photoacoustic beam deflection

The photoacoustic beam deflection technique at (lambda) equals 248 nm was employed for the measurement of the laser damage threshold of single films of magnesium fluoride deposited on superpolished calcium fluoride and fused silica substrates. Different samples were investigated. All films have similar thickness but are deposited by various techniques in different laboratories. The samples are fully characterized, both from the optical and the structural point of view, in the framework of a European Project on 'UV-coatings'. The results of these measurements are reported, along with the data on laser damage threshold, to find out which are the most significant parameters for laser applications.