DIFFRACTION FROM A SHORT-CAVITY FABRY-PEROT - APPLICATION TO PHOTOREFRACTIVE QUANTUM-WELLS

Diffraction efficiencies from absorption and index gratings in short-cavity Fabry-Perot multiple quantum well structures are strong functions of film thickness. Diffraction efficiencies of transmitted and reflected waves vary by an order of magnitude by adjusting the device thickness to bring the Fabry-Perot resonance condition close to the excitonic absorption. Asymmetric Fabry-Perot quantum-well reflection modulators produce the largest diffraction efficiencies, with input diffraction efficiencies approaching 6%. Analytic expressions for the diffraction efficiencies are derived in the Raman-Nath regime for a single thin film and for multilayer structures. These results apply in general for dynamic holography and transient dielectric gratings in thin films, but is illustrated specifically for photorefractive semiconductor quantum wells.