Antiboding and bonding lasing modes with low gain threshold in nonlocal metallic nanoshell.

Abstract

Based on a full-wave nonlocal Mie theory, we establish the spaser generation condition for compact plasmonic nanolasers in the long-wavelength limit for dielectric-metal core-shell nanoparticles. We found that there exist two lasing states arising from the hybridized antibonding and bonding modes for this coated nanolaser. By varying the surrounding medium and the gain materials, we can achieve low gain threshold for each mode with flexible radii ratios on the purpose of realistic easy fabrication. Numerical results show that nonlocal effects have different influences on the required gain threshold and gain refractive index of these two lasing modes, which may be of great importance in the design of such kind of ultrasmall nanoparticle lasers.