Radiometric Short-Term Fourier Transform analysis of photonic Doppler velocimetry recordings and detectivity limit

Photonic Doppler Velocimetry is a plug-and-play and versatile diagnostic used in dynamic physic experiments to measure velocities. When signals are analyzed using a Short-Time Fourier Transform, multiple velocities can be distinguished: for example, the velocities of moving particle-cloud appear on spectrograms.In order to estimate the back-scattering fluxes of target, we propose an original approach “PDV Radiometric analysis” resulting in an expression of time-velocity spectrograms coded in power units.Experiments involving micron-sized particles raise the issue of detection limit; particle-size limit is very difficult to evaluate. From the quantification of noise sources, we derive an estimation of the spectrogram noise leading to a detectivity limit, which may be compared to the fraction of the incoming power which has been back-scattered by the particle and then collected by the probe. This fraction increases with their size.At last, some results from laser-shock accelerated particles using two differ...