Spin–orbit splitting dependent resonant third-order nonlinear optical susceptibility in InGaN/GaN multiple quantum wells

For the transition between valence band and conduction band, the third-order nonlinear optical susceptibility χ(3) for degenerated four-wave mixing in InxGa1−xN/GaN multiple quantum wells (MQWs) has been calculated. The contributions of spin–orbit split-off energy to the resonant third-order nonlinear optical susceptibility of the modes, whose polarization is vertical to the [0 0 1] direction of the MQWs, are discussed in detail. The correlations between the peaks of χ(3), which are due to the transitions from the spin–orbit split-off energy level to first conduction subband, and the width of the quantum well and the constituents of the semiconductor material are obtained.