Well width-dependent third-order optical nonlinearities of a ZnS/CdSe cylindrical quantum dot quantum well

The third-order nonlinear susceptibilities associated with intersubband transition are theoretically calculated for ZnS/CdSe cylindrical quantum dot quantum well. The eigenenergies of electrons and wave functions in QDQW have been calculated under the effective-mass approximation by solving a three-dimensional nonlinear Schrödinger equation, and by means of compact density matrix method, the third-order nonlinear susceptibilities for third harmonic generation and quadratic electro-optic effects have been calculated for different sizes of QDQW. By increasing the width of shell well, the peaks of χTHG(3) and χQEOE(3) as functions of pump photon energy ℏωℏω will shift to the lower energy, and the intensities of the peaks will increase.