Optically tunable linear and nonlinear enhancement of index of refraction
Ramazan Şahin, PhD · · 1 min read · Updated
A pump–probe study of how the strength and phase of a control field tune the plasmonic analogue of index enhancement.
Changing a material's refractive index on demand is one route to steering light in lossy media. This paper models the plasmonic counterpart of enhancement of the index of refraction (EIR) with a semi-classical picture of coupled harmonic oscillators and studies it in a pump–probe configuration, following the probe's effective mode index as the pump's strength and phase are varied.
The coupled plasmon modes come from two L-shaped nano-ellipsoids. Going beyond an earlier classical treatment, the authors quantise the system to first and second order, which lets them track the nonlinear part of the index as well. According to the paper, a stronger pump raises the enhancement in both regimes and, through interference between the coupled modes, also reduces optical losses; shifting the pump phase moves the probe's spectral response, which the authors present as a way to tune epsilon-near-zero (ENZ) behaviour. Suggested uses include quantum technologies, propagation with compensated losses, metamaterials spanning zero to high index, and photonic switches.
This summary is based on the paper's published abstract; the author list, journal and DOI are shown in the citation box.