WHAT IS THE LOWEST REFRACTIVE-INDEX OF AN ORGANIC POLYMER

The refractive index is a key feature in the application of optical polymers. The continuous development of new materials for technological fields such as optical fibers or lenses poses the question about the fundamental physical limits of this class of materials. By using the Lorenz-Lorentz equation, we have investigated the theoretical lower limit of the refractive index of organic polymers. Starting from an extended data base, we have evaluated optimized refractive and density increments for functional groups. Using a "construction plan" for low-index polymers, we expect the lower limit to be close to 1.29. To our knowledge this is the first estimate of this fundamental limit.