A new type of optical fiber

Anderson localization, known also as “strong localization”, is a physical phenomenon that occurs when the diffusion of waves of electromagnetic or acoustic nature is inhibited by a strong disorder of the transmission medium, consequence of a high degree of impurities or defects: actually, there is the absence of the diffusion of waves that remain confined in a delimited area. The phenomenon involves also laser beams (on the other hand, light signals are just a form of electromagnetic waves) that, in presence of strong disorder, can remain entangled in an area creating very bright points. Exploiting this phenomenon, a team of researchers of the Institute of Complex Systems and of the Institute for Physical-Chemical Processes of CNR, in collaboration with the Italian Institute of Technology (IIT), the Department of Physics of La Sapienza and the University of Wisconsin, has implemented a new type of optical fiber where an escape way is created for the entangled light, which in that way follows a desired path instead of diffusing in all directions. It seems that these characteristics can open new prospects both in the telecommunication field, with the transport of a bigger quantity of information than with conventional fibers crossed by a single light space channel, and in the laser surgery field. In detail, the new optical fiber is constituted by tubular structures of a material resembling common plastic, purposely arranged in disordered way as it happens with a handful of matches or spaghetti positioned at random in a box. Anderson localization entangles the ray of light in very narrow spaces and, through a particular spatial light modulator, researchers succeeded in concentrating and controlling the light beam shape, thus creating the conditions to transmit more signals on the same fiber using the various spatial channels inside the disordered structure. In surgery, since a cut is the more precise the more the laser light is focused, the new fibers might increase the precision of laser scalpels.