1. The main portion of the beam is used to illuminate the flow. This may be done in a number of ways depending on the flow to be measured, but typically will be formed into a sheet in order to elucidate some cross-section of interest, or will be coupled into a fiber-optic cable for relaying. A sCMOS pco.edge camera is used for each signal detector. These cameras feature very low noise and pixel blooming, thus increasing spatial resolution capabilities. Each camera has an associated iodine absorption cell, of the same type as is used for the reference photodiode. As the power supply sweeps through a pre-set voltage range, the photodiode collects intensity data while each camera snaps an image. The actual voltage on the piezoelectric element is also continuously monitored. B. Experimental Configuration for Validation
2. LOCALIZED FLUID FLOW MEASUREMENTS WITH AN He–Ne LASER SPECTROMETER