Fig. 4: Electrotunable liquid microlenses.
a Schematic and b optical microscopy images of a microlens based on a 60-µm sulfur droplet with a converging distance of 45 µm. c Measured intensity profile with cross sections in the xy plane. d Calculated intensity profile from ray tracing, scale bar in (b–d) is 20 µm. e The focal length of the microlenses can be tuned as a function of the diameter of the sulfur droplets, scale bar in (e) is 200 µm. The squares are experimental data and the black dots are simulated data. f Imaging of the letter “S” patterned on a cover glass slide with sulfur droplet-based microlenses, with g reduced, h equal, and i magnified images. The dashed lines in the schematics denoted by H indicate the location of the principal plane of the microlenses. scale bar in (g–i) is 20 µm.
