Fig. 3: Characterization of focal length and focusing efficiency.

a Graph of focal length plotted against wavelength for lower and higher numerical aperture (NA) diffractive lenses, geometric hybrid lenses, and GRIN hybrid lenses. Each data point was averaged across ten printed lenses. The diffractive lenses experienced stronger negative dispersion than the hybrid lenses. b Graph of measured focusing efficiency plotted against wavelength for each type of lens. Each data point was averaged across the ten printed lenses. Error bars represent the maximum and minimum values across the ten samples. c Schematic depicting the experimental setup for measuring microlens focusing efficiency. Microlenses (left of the figure) are placed on a motorized stage and illuminated by collimated lasers. A 50:50 beam splitter transmits half of the light to a camera and half to a power meter, allowing the simultaneous alignment of the pinhole and the power measurement.