Abstract
Using high-speed picometrology, the complete cluster-to-film dielectric trajectories of ultra-thin gold films on silica are measured at 488 nm and 532 nm wavelengths for increasing mass-equivalent thickness from 0.2 nm to 10 nm. The trajectories are parametric curves on the complex dielectric plane that consist of three distinct regimes with two turning points. The thinnest regime (0.2 nm - 0.6 nm) exhibits increasing dipole density up to the turning point for the real part of the dielectric function at which the clusters begin to acquire metallic character. The mid-thickness regime (0.6 nm similar to 2 nm) shows a linear trajectory approaching the turning point for the imaginary part of the dielectric function. The third regime, from 2 nm to 10 nm, clearly displays the Drude circle, with no observable feature at the geometric percolation transition. (C) 2010 Optical Society of America
Published in:
Optics Express 18,24 (2010) 24859-24867;
Date of Version
November 2010
Recommended Citation
Wang, X. F.; Chen, K. P.; Zhao, M.; and Nolte, D. D., "Refractive index and dielectric constant evolution of ultra-thin gold from clusters
to films" (2010). Department of Physics and Astronomy Faculty Publications. Paper 1338.
https://docs.lib.purdue.edu/physics_articles/1338