All-optical switch based on two-dimensional asymmetric electromagnetically induced grating in nanohybrid systems

This study investigates (EIG) in a nanohybrid configuration involving a semiconductor quantum dot (SQD) and a core-shell bimetallic nanoparticle coated with graphene. The goal is to optimize interactions between plasmons and excitons. This is achieved by utilizing nanoparticles covered with graphene, which enhances control over surface plasmons. These interactions decrease light absorption by quantum dots. At the same time, they enhance the presence of coherent states and quantum interference. The innovative aspect of this model lies in its ability to produce a two-dimensional asymmetric diffraction grating. This is accomplished by modulating the phase within a closed-loop structure and utilizing the nonlinear multi-wave mixing phenomenon, without needing to adjust other system parameters. More specifically, altering the phase of the incident fields produces an asymmetric diffraction grating with an efficiency exceeding 50%. Similarly, varying the frequency of the probing field results in an asymmetric diffraction grating with efficiencies exceeding 40%. This technology has the potential to enhance optical systems, such as all-optical switches in communications, by simplifying the alteration of laser beam phases and probe field frequencies.