The first measurements using Laser Doppler Velocimetry are currently being carried out @TROVA. These are the first-ever velocity measurements within a non-ideal compressible-fluid flows in the close proximity of the liquid-vapour saturation curve. The flow seeding required the design and construction of a the pressurised seeding apparatus shown in the picture.
Pressurised seeding system
Laser source and photodetector.
Note the (very cool!) laser safety goggles...