Two-phase flows hold an interest in many areas of science and engineering. In the safety field, one such topic is the accidental release of flammable and toxic pressure-liquefied gases. In case of such a release, a flashing vapor explosion takes place resulting in a very dense two-phase cloud. If the released substance is flammable, this cloud can be combustible and can lead to deflagration or detonation. For understanding the source processes of flashing and risk assessment, data related to cloud characteristics (i.e. droplet size, velocity etc.) is needed especially in the near region of the release. Due to the non-equilibrium nature of the near field regions accurate data measurement is not possible with intrusive techniques. Therefore, laser-based optical techniques (like Particle Image Velocimetry (PIV), Particle Tracking Velocimetry and Sizing (PTVS), Phase Doppler Anemometry (PDA) etc.) present the only possibility to obtain information for particle diameter and velocity evolution in this harsh environment. The main objective of the present work is to explore the potential of non-intrusive laser based techniques such as PDA and PIV on the characterization of a two-phase R-134A flashing jet. The encountered problems were explained. An attempt was made to measure the velocity of different droplet classes using Multi-intensity-layer PIV.