Researchers from the University of Cincinnati and the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio have announced the results of their study of a fluorine-based chromophore that may find applications in high-density optical data storage. Reporting in the July 17 issue of Applied Physics Letters, the team also found that it could optically write Mach-Zehnder interferometers into poly(N-vinylcarbazole) films doped with the substance, known as AF-50. The scientists used the 325-nm line from an 8-mW HeCd laser to write information on the doped polymer films. Photoluminescence studies indicate that the laser radiation induces an irreversible chemical change in the chromophore. A 20-mW argon-ion laser operating at 488 nm was subsequently used to read the information on the sample.