The material they chose for the artificial eyes was an epoxy resin that cures into a hardened form when exposed to ultraviolet light. They poured the resin into the dimpled molds, baked it at a low temperature just long enough to slightly harden the material, then turned out the contents: little resin hemispheres with a surface packed with 8,700 raised mounds. When struck by a beam of light, each of these mounds acts as a lens, focusing the light and sending it into the material below. Like a welder's torch burning a hole into metal, over time the focused light beams etch holes in the resin creating the tiny channels called self-written waveguides.
Because these channels are formed at the angle of the light beams that strike them, Lee used a condenser lens to bend his light source into a spoke-like pattern of beams that converges on the eye's dome. The end result is that the waveguides pierce the resin at angles that head toward the center of the dome, just like the converging ommatidia of an insect eye.
Because the microlenses create the waveguides, each microlens is perfectly aligned with its waveguide. The self-alignment, self-writing processes are crucial to the creation of the artificial compound eye, said Lee, because these processes will also align the microlenses and waveguides with the pixels of CCDs and spectroscopes.
"Who knows? Maybe this is how insect eyes are created, too," said Lee. "First, there are the lenses, and then as light keeps coming in, they make their own optical paths and connect with the visual system."
Lee speculates that the artificial compound eyes will be put to use within a few years. Their first applications may be in ultra-thin camera phones. After that, he expects to see them used in camcorders for omnidirectional surveillance imaging and such uses as small, hidden, wearable cameras.