Implementation of Fourier Demodulation Synthetic Schlieren for Characterization of Surface Waves on a Parametrically-Forced Fluid Surface

Oil droplets bouncing on a parametrically-forced fluid surface provide an accessible model for studying fluid analogs to quantum mechanics. Other researchers have employed a variety of imaging techniques and droplet generators to capture and characterize these phenomena. In this work, we implemented Fourier Demodulation Synthetic Schlieren (FDSS) to analyze waves generated by oil droplets bouncing on a vertically oscillating bath. We constructed a droplet generation system and synchronized it with a high-speed camera, carefully mounting both independently from the shaker table to minimize vibrations. By managing thermal effects and tuning the droplet generator parameters (e.g., the nozzle diameter or the duration of the voltage pulse applied to the piezo), we achieved reliable production of droplets at the desired scale. After implementing FDSS, we validated our results against published data. We then used our system to characterize the waves generated by an infrared laser pulsing on the bath surface and how these waves can mediate the interaction between the laser and the bouncing drops.