Control of electromagnetically induced grating by surface plasmon and tunneling in a hybrid quantum dot-metal nanoparticle system.

We investigate the electromagnetically induced grating (EIG) in a quantum dot-metal nanoparticle (QD-MNP) hybrid system. The EIG can be controlled and improved by the surface plasmon effect and the interdot tunneling effect between quantum dots. By manipulating the tunneling effect and the QD-MNP distance, not only the first-order diffraction intensity of the grating can be efficiently enhanced, but also the EIG can be switched from the absorption grating to the gain grating. Almost two times the first-order diffraction efficiencies can be achieved in the gain gratings compared with the absorption gratings.