Ultra-thin, colorful optical coatings
Optical coatings are widely used to control the reflection and transmission of light from materials such as lenses, mirrors, and glass. Conventional coatings – which work on the same thin-film interference principle that gives an oil slick its colorful appearance – are typically sensitive to the angle of viewing, highly transparent, and relatively thick. This invention utilizes ultra-thin layers of a highly-absorbing dielectric, such as germanium, to achieve dramatic color effects. Coatings that are just 10 nm thick can create colorful reflected light that varies little with angle. Moreover, the color can be changed by altering the coating thickness by just a few atomic layers. Remarkably, the technology works well both with polished materials, such as metal, and rough substrates, like paper. There are numerous application possibilities, including colored solar cells, ultrathin photodetectors and colorful materials for jewelry, printing, and art.
Intellectual Property Status: Patent(s) Pending