The Journal of Physical Chemistry C
Control of Self-Kerr Nonlinearity in a Driven Coupled Semiconductor Quantum Dot–Metal Nanoparticle Structure
Spyridon G. Kosionis, Emmanuel Paspalakis
Abstract
The self-Kerr nonlinear optical response of a probe field is investigated in the presence of a near-resonant pump field in coupled metal nanoparticle (MNP)–semiconductor quantum dot (SQD) nanostructures. The study of the spectra is based on the solution of the resulted density matrix equations for the case of a colloidal CdSe-based SQD–(Au)MNP molecule, as well as for an epitaxial SQD structure coupled to an Au nanoparticle. It is demonstrated that below a critical value of the interparticle distance the susceptibility of each distinct component of the structure exhibits a characteristic single-resonance spectrum, whereas above this value, the spectrum has three resonances. This phenomenon can be understood in terms of the theory of exciton–plasmon quantum metastates. In addition, the conditions under which optical transparency occurs with a concurrent positive self-phase-modulation coefficient are also identified.