NONLINEAR INTERSUBBAND PLASMON POLARITONS IN A QUANTUM-WELL STRUCTURE

We study nonlinear intersubband plasmon polaritons in a quantum-well s tructure. Using a microscopic local-field formalism, the dispersion re lation of the nonlinear plasmon polaritons in a single quantum well is derived. For a two-level GaAs/AlGaAs quantum well, the dispersion rel ation is solved numerically. The numerical results show the strong int ensity dependence of the mode index appearing at the guided power of s imilar to mW/mm for the photon energy somewhat above the intersubband splitting. When the guided energy becomes larger, the power dependence of the wave vector of the plasmon wave exhibits saturation behaviour.