When can we see micromotion? Experimental and theoretical analysis of the ChiSCAT scheme.

We present an in-depth analysis of ChiSCAT, a recently introduced interferometric microscopy scheme to detect recurring micromotion events in cells. Experimentally, we demonstrate that illumination with low-coherence sources can greatly improve the robustness of the scheme to vibrations. We analyze the theoretical performance of ChiSCAT under various noise models, particularly photon shot noise and noise dominated by cellular motions other than the signal. We finally propose ways to improve performance, especially in a setting dominated by cell motions, and conclude with an outlook on potential future directions.