Highly efficient third-harmonic generation from resonant intersubband transitions in core/shell spherical quantum dots

The efficient third-harmonic generation related to intersubband transitions in GaAs/AlGaAs core/shell spherical quantum dots is studied in detail. An analytic formula for the third-harmonic-generation susceptibility under the condition of the triple resonance is derived by the compact density matrix approach and the iterative procedure. The numerical results show that a very large third-harmonic generation susceptibility of the order of magnitude of 10−12 (m/V)2 can be obtained by choosing properly the radius of the spherical quantum dot and the angular frequency of incident light to satisfy the triple resonance condition. In addition, the influence of the relaxation time on the third-harmonic generation susceptibility is clarified. These properties make spherical core/shell quantum dots be potential candidates for extensive applications in optical information storage and nanophotonic devices.