Micropatterning of silk proteins for soft bioactive diffractive optical elements

We present a method of making green, bioactive, low cost diffractive optical elements (DOEs) using silk fibroin proteins. DOEs usually permit a reduction in the number of optical elements in a design, reducing costs and lens weight. Compared with conventional DOEs made of glass or other transparent materials, silk protein based DOE structures are usually more flexible, thinner, lighter, and more importantly biocompatible and bioactive. The "green" silk protein films can be used to "lock" and "unlock" the information stored in DOE made on silica with only water being used. The whole process is simple, inexpensive, and environment-friendly.