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We theoretically demonstrated a class of plasmonic coupled elliptical nanostructure for achieving a spaser or a nanolaser with high intensity. The plasmonic ellipse is made up of gold film substrate. The proposed structure is then trialed for various light polarizations, moreover, a simple elliptical nanostructure has been chosen primarily from which different cases have been formed by geometry alteration. The structure supports strong coupled resonance mode i.e. localized surface plasmon (LSP). The localized surface plasmon resonance (LSPR) of the investigated system is numerically examined using the finite-element method (FEM). The calculations showed that the LSPR peaks and the local field intensity or near field enhancement (NFE) of the active nanosystem can be amplified to higher values by introducing symmetry-breaking techniques in the proposed ellipse and its variants. The coupled nanostructure having different stages of wavelengths can be excited with different plasmonic resonance modes by the selection of suitable gain media. In addition, a small-sized nanolaser with high tunability range can be developed using this nanostructure. The spaser phenomena are achieved at several wavelengths by changing light polarization and structure alteration methods. Giant localized field enhancement and high LSPR values enable the proposed model to be highly appealing for sensing applications, surface-enhanced Raman spectroscopy, and much more. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]