Imaging of live cells was carried out using evanescent-wave excitation on a polymer waveguide chip. Integrated waveguide-based interferometric light modulators were fabricated in order to demonstrate on-chip control of excitation light, e.g., for time-lapse fluorescence microscopy. When combined with a sensitive high-resolution imaging system, the integrated waveguide-excitation platform provides an ideal method of near-surface studies of live cells, where photobleaching and/or phototoxicity effects are of critical concern.