Engineering Symmetry-Breaking Nanocrescent Arrays for Nanolasing

This paper describes a symmetry-breaking plasmonic lattice structure that can support narrow resonances as optical feedback for nanolasing. A scalable technique is developed to fabricate nanocrescent arrays with low-structural symmetry unit cells to achieve in-plane quadrupolar lattice plasmon modes. These lattice plasmons with extremely narrow linewidths preserve nonzero net dipole moments under normal excitation. Ultrafast band-edge lasing can be switched on and off by changing the polarization of the incident pump light. The quadrupolar lattice plasmon lasing process is simulated with a semi-quantum model and the sharp tips on the nanocrescents accelerate the lasing buildup process and enhance stimulated emission.