Imaging of acoustic pressure modes in opto-mechano-fluidic resonators with a single particle probe

Opto-mechano-fluidic resonators (OMFRs) are a platform for high-throughput sensing of the mechanical properties of freely flowing microparticles in arbitrary media. Experimental extraction of OMFR mode shapes, especially the acoustic pressure field within the fluidic core, is essential for determining sensitivity and for extracting the particle parameters. Here, we demonstrate an imaging technique for simultaneously capturing the spatially distributed acoustic pressure fields of multiple vibrational modes in the OMFR system. The mechanism operates using microparticles as perturbative imaging probes and potentially reveals the inverse path towards multimode inertial detection of the particles themselves.