@article {Wuestner20113525,
	title = {Gain and plasmon dynamics in active negative-index metamaterials},
	journal = {Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences},
	volume = {369},
	number = {1950},
	year = {2011},
	note = {cited By 56},
	pages = {3525-3550},
	abstract = {Photonic metamaterials allow for a range of exciting applications unattainable with ordinary dielectrics. However, the metallic nature of their meta-atoms may result in increased optical losses. Gain-enhanced metamaterials are a potential solution to this problem, but the conception of realistic, three-dimensional designs is a challenging task. Starting from fundamental electrodynamic and quantum mechanical equations, we establish and deploy a rigorous theoretical model for the spatial and temporal interaction of lightwaves with free and bound electrons inside and around metallic (nano-) structures and gain media. The derived numerical framework allows us to self-consistently study the dynamics and impact of the coherent plasmon-gain interaction, nonlinear saturation, field enhancement, radiative damping and spatial dispersion. Using numerical pump-probe experiments on a double-fishnet metamaterial structure with dye molecule inclusions, we investigate the build-up of the inversion profile and the formation of the plasmonic modes in a low-Q cavity. We find that full loss compensation occurs in a regime where the real part of the effective refractive index of the metamaterial becomes more negative compared to the passive case. Our results provide a deep insight into how internal processes affect the overall optical properties of active photonic metamaterials fostering new approaches to the design of practical, loss-compensated plasmonic nanostructures. {\textcopyright} 2011 The Royal Society.},
	doi = {10.1098/rsta.2011.0140},
	url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053006023\&doi=10.1098\%2frsta.2011.0140\&partnerID=40\&md5=d71445e1ffa51d484758b512027f58bf},
	author = {Wuestner, S. and Pusch, A. and K. L. Tsakmakidis and Hamm, J.M. and Hess, O.}
}
