High-bandwidth diffraction of femtosecond pulses from photorefractive quantum wells

Summary form only given. Photorefractive quantum wells are attractive media for dynamic holography due to their high sensitivities, small saturation intensities, and short response times compared to bulk photorefractives. Such properties are desirable in applications like dynamic femtosecond pulse shaping and spectral holography. However, these devices have suffered from a limited diffractive bandwidth, resulting from the resonant nature of the electro-optic response of multiple quantum wells. The operating bandwidth of a GaAs/AlGaAs photorefractive multiple quantum well device is on the order of 3 nm, in sharp contrast with the 10 nm bandwidth of a 100-fsec pulse. We have overcome the large bandwidth mismatch between femtosecond pulses and photorefractive quantum wells operating via the resonant Franz-Keldysh effect by using density-of-states engineering.