Spatial modulation of the dielectric function using free carriers and/or coherent effects in quantum-well semiconductor microcavity

Results on picosecond degenerate four-wave mixing in semiconductor microcavity are presented. The device is made of GaInAs/GaInAsP multiple quantum wells enclosed in an asymmetric Fabry–Perot microcavity 80%–98%. For incident photon energies below the excitonic energy, the spatial modulation of the dielectric function can be generated by free carriers and/or coherent effects. We show that the last one can be significant; an input diffraction efficiency of 2% with only 1 μJ/cm2 pump fluence is achieved. This result demonstrates a new way to obtain ultrafast, sensitive, and low-dissipative devices.