Scattering dominated spatial coherence and phase correlation properties in plasmonic lattice lasers

Abstract

We present a comprehensive study of the polarization and spatial coherence properties of the lasing modes supported by a 4-fold symmetric plasmonic lattice. We can distinguish the scattering induced effects from the lattice geometry induced effects by modifying only the diameter of the particles while keeping the lattice geometry constant. Customized interferometric measurements reveal that the lasing emission undergoes a drastic change from 1D to 2D spatial coherence with increasing particle size, accompanied with dramatic changes in the far field polarization and beaming properties. By utilizing T-matrix scattering simulations, we reveal the physical mechanism governing this transition. In particular, we find that there exists increased radiative coupling in the diagonal directions at the plane of the lattice when the particle diameter is increased. Finally, we demonstrate that the x- and y-polarized (degenerate) lasing modes become phase locked with sufficiently large particles.

High-Order Χ Points Driven Multi-Polarized Emission in a Square Plasmonic Lattice

“…In contrast, polarization imagers require the incorporation of line-grid polarizers oriented in four distinct directions within the camera. Given that 2D plasmonic lattices are characterized by an abundance of high-symmetry points, and considering that the directionality and polarization dependence of nanoparticle scattering can dictate the spatial symmetry and polarization characteristics of the emission beams [29][30][31][32] , a single sample has the potential to produce a multitude of multi-polarized beams. This paves the way for novel platforms in optical communication and polarized imaging.…”