Control of Kerr nonlinearity in a four-level quantum system near a plasmonic nanostructure

We investigate the nonlinear optical response of a four-level double-V-type quantum system interacting with a pair of weak probe fields while located near a two-dimensional array of metal-coated dielectric nanospheres. Such a quantum system contains a V-type subsystem interacting with surface plasmons, and another V-type subsystem interacting with the free-space vacuum. A distinctive feature of the proposed setup is its sensitivity to the relative phase of the applied fields when placed near the plasmonic nanostructure. We demonstrate that due to the presence of the plasmonic nanostructure, the third-order (Kerr-type) susceptibility for one of the laser fields can be significantly modified while another probe field is acting. Moreover, the Kerr nonlinearity of the system can be controlled and even enhanced by varying the distance of the quantum system from the plasmonic nanostructure. We also show that the Kerr nonlinearity of such a system can be controlled by adjusting the relative phase of the applied fields. The results obtained may find potential applications in on-chip nanoscale photonic devices.

Automated summary

The nonlinear optical response of a four-level double-V-type quantum system interacting with a two-dimensional array of metal-coated dielectric nanospheres was investigated. It was found that the Kerr nonlinearity of the system can be controlled and enhanced by varying the distance of the quantum system from the plasmonic nanostructure, and adjusting the relative phase of the applied fields can change the polarization rate of one of the laser fields.