Femtosecond time-reversal in photorefractive polymers

Summary form only given. Time-domain holography has become increasingly important for ultrafast data processing. However, spectral holeburning media that have previously proven their capability for femtosecond data processing are limited by their inhomogeneously broadened absorption bandwidth. Photorefractive polymers are low cost, mass producible and operate at room temperature. CW diffraction efficiencies near 100% have been reported, and infrared-sensitive materials have recently become available. In order to use PR polymers for information processing, they need to work with ultrashort pulses that have a large bandwidth and yield sufficient diffraction efficiencies. We used a standard two-beam mixing geometry in order to measure the diffraction efficiencies. Reading the hologram with pulsed lasers without the etalon and cross-correlating the diffracted beam with a 130 fs reference beam, different pulse-trains are obtained depending whether we look in the original or in the phase conjugated direction. This demonstrates for the first time femtosecond time-reversal on a 130 fs time scale in the photorefractive polymer at room temperature around 800 nm.