Seeing Color with a PhotodetectorCategory: Science & Technology
Posted: August 26, 2014 11:05AM
Color blindness affects only about nine percent of people, but just about every digital camera is unable to discern color with just its detector. Color images are the result of filters external to the photodetector that separate incoming light to the red, green, and blue we are familiar with. Researchers at Rice University however, have developed a photodetector with color sensitivity, while studying cephalopods.
How are cephalopods like squids related? These species have very odd skin, which the Office of Naval Research wants to be studied. Cephalopods are color blind, but it is suspected that they can still detect color with their skin, and it was from this hypothesis that the Rice researchers developed the new photodetector. On top of the typical silicon photodetector, the researchers put a layer of aluminum that was etched into, using a process commonly used in CMOS process. The thickness of an oxide layer was also manipulated to create a plasmonic grate on the detector's surface. With such control, grating could be tuned to only allow certain frequencies of light through, and to focus that light onto the detector.
Unlike the filters traditionally used in digital cameras, this plasmonic grating can be built directly onto silicon photodetectors using standard CMOS techniques. Beyond the advantages of being part of the chip, this grating is also smaller and simpler and the filters, all while mimicking how organisms detect colors.
Source: Rice University