Laser doppler velocimetry
Laser Doppler Velocimetry is a well established method for analysing particle movement at a single point, either in a gas or a liquid. This information is typically collected using two intersecting collimated laser beams. The beams intersect and interfere in the region for analysis. The particles passing through this region reflect light and from this data it is possible to measure the Doppler shift and therefore velocity of the particles.
The laser source suitable for such applications needs to have long coherence length, operate single longitudinal mode, and have good power and noise stability. Cobolt CW DPSS lasers are thus perfectly suited to such an application. In addition, Cobolt's range of DPSS lasers also includes shorter wavelengths, such as 355nm, that can be used to give additional information about the size of the particles.
