Semiconductor quantum dot mixture as a lossless negative dielectric constant optical material

Prospects for a lossless negative dielectric constant material for optical devices are studied. Simulations show that, with sufficient gain, a mixture of two semiconductor quantum dots can produce an isotropic effective dielectric constant that is lossless and negative. Both analytical homogenizations based on the work of Maxwell Garnett and frequency-dependent dielectric constants from inversion of numerical computations of scattered fields are used to establish the dielectric constants of a mixture of gain and loss dots. Over length scales where homogenization is meaningful, this material could be used to achieve lossless ``metal-insulator'' optical waveguides and hence a small optical mode volume.