IBM Corp reports that scientists at its Almaden Research Center in San Jose have discovered the world’s first polymer with optical characteristics previously found only in a few small and expensive crystals: the company says that the discovery holds out the possibility of instant cameras that generate holograms, optical storage devices that can hold up to a 100M-bits in a single spot the size of a pin head, or goggles that automatically diffuse intense light to protect their wearers from being blinded by lasers; the polymer is a mixture of a new type of epoxy and an organic material used in copiers and laser printers and is the first reported to to exhibit the photorefractive effect where illumination by light causes electrical charges within the material to move, altering its refractive index; when two laser beams cross within a photorefractive material, they create a pattern of electrical charge similar to a hologram that changes the optical properties of the material through which it is passing; the IBM scientists started with an epoxy polymer called BisA-NPDA that colleagues had devised in 1988 to have an index of refraction that would change when exposed to an electric field, and added an organic photoconductor material, DEH, used as the charge transport agent in copiers, leading to a polymer mixture that exhibited a modest photorefractive effect – a diffraction efficiency of 0.01% to 0.001%, and they have since achieved a 10 times stronger effect in a mixture of DEH and another epoxy – but a diffraction efficiency of over 10% is needed for applications.
