Patent ID: 10921345

Abstract:
The invention relates to a method for the contactless determining of the speed of a fluid flow and the concentration of at least one analyte therein, wherein a) the flow speed is measured by means of laser Doppler anemometry (LDA) using tracer particles which pass through an interference fringe pattern in the intersection region of two coherent monochromatic light beams and thereby generate a scattered light signal; and b) the concentration of the at least one analyte is measured by means of Raman spectroscopy, wherein a monochromatic light beam is radiated in and the Raman spectrum of the light inelastically scattered on the analyte molecules in the flow is recorded; wherein c) a single light source is used for both the LDA and the Raman spectroscopy, such that both measurements are carried out in the intersection region of two two coherent light beams coming from the light source, wherein the speed is measured by photons elastically scattered onto the tracer particles, and the concentration is measured by photons inelastically scattered onto analyte molecules; and d) for the purposes of speed measurement, the elastically back-scattered photons are detected by the same lens optic that is also used for the radiation of the light beams.