Artificial compound eyes

Unlike mammals, whose two eyes each have a single lens that focuses images onto the retina, insects and crustaceans have compound eyes: curved surfaces packed with tens to thousands of individual optical units called ommatidia. Each ommatidium consists of a faceted lens that focuses light through a crystalline cone onto a waveguide called a rhabdom, which is formed inside photoreceptor cells. Compound eyes are highly sensitive to motion and, because each ommatidium can view a different angle, a fused image from all the ommatidia can produce a very wide-angle, high-resolution image. A team led by Luke Lee at the University of California, Berkeley, has now succeeded in making artificial compound eyes. The researchers start with a spherical array of microlenses fabricated by molding a photosensitive polymer to a microtemplate. Next, the researchers make self-aligned waveguides behind the lenses by using a condenser lens to spherically illuminate the microlens array with UV light. The light causes the polymer behind each microlens to cross-link, producing the waveguide cores; subsequent baking completes the waveguides. As shown here, the artificial compound eye (right) is similar in structure to the honeybee’s eye (left) and has comparable optical characteristics. The researchers envision a broad range of applications, including data storage and read-out, medical diagnostics, and photography. (K.-H. Jeong et al., Science 312 , 557, 2006 http://dx.doi.org/10.1126/science.1123053 .)