High Near-Field Enhancement in Plasmonic Coupled Nanostructure for Spaser Application

We theoretically demonstrated a kind of plasmon coupled elliptical/crescent nanostructure to achieve a vast range of applications based on nanolaser or spaser with high intensity. To overcome the ohmic losses, the plasmon ellipse is composed of the gold film substrate with a gain media. A simple ellipse has been chosen from which a variety of dimer configurations have been formed by the symmetry alteration technique which is then tested for different light polarizations and gap variations. The proposed model supports localized surface plasmon resonance mode (LSPR). Moreover, the localized surface plasmon resonance (LSPR) property of the proposed nanostructure is numerically analysed by the finite-element method (FEM), and the results show that the electric field intensity (EFI) can be amplified to a large value by symmetry breaking in the elliptical nanostructure. Various plasmon modes can be excited by selecting the appropriate gain media. In addition to this, a compact tuneable multi-wavelength nanolaser (spaser) can be developed by using this model.