Teflon film
The photograph shows the image of a ~1um teflon film on a photonic crystal fiber (PCF) taken under a microscope but imaged with a one time usable cheap camera commonly available in supermarkets and stores. The purpose of the experiment was to selectively infiltrate the air holes in the PCF with different refractive indices to tune the bandgap guidance properties of the PCF. This experiment was carried out in Dr. Tsing-Hua Her's lab at The University of North Carolina at Charlotte.
—Himansu S. Pattanaik CREOL, The College of Optics and Photonics