A Study of Degenerate Four-Wave Mixing and Phase Conjugation in Metallic Nanohybrids

A theory of degenerate four-wave mixing (DFWM) and phase conjugation is developed for metallic nanohybrids, which consist of an ensemble of interacting metallic nanoshells and noninteracting quantum dots (QDs). It is considered that three incident waves are applied to the metallic nanohybrid, and they produce a fourth output mixed wave. These waves induce dipoles in metallic nanoshells, generating surface plasmon polaritons, and interact with each other via the dipole-dipole interactions (DDI). In DFWM, the input and output waves travel in opposite directions, and this retroreflective nature is responsible for the phenomenon of phase conjugation. The analytical expressions for the input transmitted and output reflected wave intensities are calculated in the presence of the surface plasmon polaritons (SPPs) and the DDI polaritons. It is demonstrated that the phase conjugation, the phase coherent phenomena, and the intensities of both input transmitted and output reflected waves are enhanced due to SPPs and DDI polaritons. These findings indicate that the nanohybrid acts as a phase conjugate device and a phase coherent optical amplifier, which can be applied to fabricate optical nanoamplifiers, phase conjugate mirrors, and nanosensors by measuring the intensity of the output reflected wave. The four-wave mixing and phase conjugation are studied for plasmonic nanohybrids containing metallic nanoparticles and quantum dots in presence of the dipole-dipole interaction and surface plasmon polaritons. Four-wave mixing analytical expressions are found and are useful for scientists and engineers to perform new experiments. It is found that the nanohybrid acts as phase conjugate devices and phase coherent optical amplifiers. image