Ultrafast, room-temperature, resonance-enhanced third-order optical susceptibility tensor of an AlGaAs/GaAs quantum well.

The ultrafast, room-temperature, resonance-enhanced third-order nonlinear susceptibility tensor of an AlGaAs/ GaAs quantum well is determined. A single 6-nm GaAs quantum well embedded in a waveguide of 382-nm mode size increases the |chi((3))| from a bulk-material level of 8 x 10(-11) esu +/-20% to 6 x 10(-10) esu +/-20%. The anisotropy of the diagonal elements |chi((3))(1111), |chi((3))(2222)| and their correlation with the off-diagonal elements |chi((3))(1212)|, |chi((3))(2121)| are consistent with the one-photon resonance mechanism.