The incident radiation are amplified light pulses originating from the Coherent-Mira Ti:Sapphire laser system (100 fs long, 2 microjoules per pulse at 800 nm).

Second harmonic radiation generated in direction of specular reflection is detected by a photon counting system synchronized with the laser amplification unit. Growth and structure of thin surface layers adsorbed on various kinds of solid substrates can be probed in-situ during deposition from the vapour or liquid phase.