Photographs of bubbles in the microfluidics system taken using brightfield and DIRI.

<p>This image was acquired using a 2× objective lens (NA 0.08) and an exposure time of 10 ms. (5a) Photograph obtained with brightfield illumination alone. (5b) Photograph obtained by simultaneous using brightfield illumination and DIRI (Darkfield Internal Reflection Illumination). (5c) Photograph obtained with DIRI alone.