The measurement of particles’ velocity, size, and concentration is crucial for a wide range of industrial, environmental, and biological applications. These include particle characterization in metallurgical and chemical processing, aerosol monitoring, dust measurement in air, and flow analysis techniques such as Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV). Most existing techniques provide measurements for only one parameter, such as size, concentration, or velocity. Some of the most accurate methods, including the Visibility technique and the Phase Doppler technique, rely on optical interferometry. These techniques, use setups similar to those used in LDV and allow simultaneous measurement of velocity, particle concentration, and size, but their high cost limits their use in research applications.

In this thesis, we aim to develop cost-effective techniques for the simultaneous measurement of particles’ velocity and concentration, as well as velocity and size, using laser Bessel beams. Two experimental setups were constructed:​ One setup was designed to measure solid surface velocity and particle size, using various types of sandpaper with particle sizes ranging from 16 to 192 μm on a linear stage with velocities between 20 mm/s and 60 mm/s. Another setup was developed to measure the velocities and concentrations of moving particles, with a size less than 30 μm, in a water tank fluid flow system giving velocities from 0.88 m/s to 1.16 m/s. The linear stage experiments showed that larger particles produced fewer peaks but higher total intensities in time-intensity signals. In the water stream experiments, higher particle concentrations increased total intensity, confirming the system's effectiveness for concentration measurement.

Numerical simulations and experimental measurements were successfully conducted, demonstrating the proof-of-concept for these techniques.