Gain assisted nanocomposite multilayers with near zero permittivity modulus at visible frequencies

We have fabricated a nano-laminate by alternating metal and gain medium layers, the gain dielectric consisting of a polymer incorporating optically pumped dye molecules. From standard reflection-transmission experiments, we show that, at a visible wavelength, both the real and the imaginary parts of the permittivity epsilon(parallel to) attain very small values and we measure, at lambda = 604 nm, vertical bar epsilon(parallel to)vertical bar = 0.04 which is 21.5% smaller than its value in the absence of optical pumping. Our investigation thus proves that a medium with a permittivity with very small modulus, a key condition promising efficient subwavelength optical steering, can be actually synthesized. (C) 2011American Institute of Physics. [doi:10.1063/1.3665414]