Abstract

Transient holographic gratings using third-order nonlinear optical processes have been suggested as possible elements for a variety of optical applications, particularly in the areas of interconnection networks and optical computing. Many of the materials suggested for applications relating to holographic optical processing rely on effects such as photorefractivity or photo-isomerization, both of which occur on time scales of milliseconds to minutes [1]. While these materials are well suited to applications such as optical storage, faster materials have a higher probability of proving useful for real-time processing. Recently it has been discovered that in certain polymers doped with C₆₀, charge transfer occurs after excitation across the π – π^* energy gap of the polymer to the dopant C₆₀ molecules [2]. Using transient absorption measurements, it has been shown that this charge- transfer process occcurs at times shorter than 300 fs, and can persist up to millisecond time-scales. Since the third order nonlinear optical susceptibility, χ⁽³⁾, includes a component which is related to the excited charge distribution, charge transfer to C₆₀ can be used to increase the lifetime of this incoherent contribution to χ⁽³⁾ in polymers.

© 1996 Optical Society of America