Angle dependence of two-wave mixing efficiency in photorefractive multiple quantum wells

The authors have investigated how two-wave mixing efficiency changes as a function of angle tuning while crossing over from the Raman-Nath diffraction to the Bragg diffraction in AlGaAs/GaAs photorefractive multiple quantum wells (PRQWs). They have shown that by changing the inclination angle of the PRQW, the apparent thickness of the PRQW (as seen by the mixing beams) can become larger than the grating fringe spacing. This moves the wave mixing from Raman-Nath diffraction to Bragg diffraction and causes an enhancement in the mixing efficiency at smaller fringe spacing.