Abstract

The race for engineering metamaterials with a negative refractive index in the optical range has been stimulated by the realization of negative index metamaterials for GHz frequencies six years ago [1]. Very recently, metamaterials have been designed that show a negative rea part of the refractive index at the telecom wavelength of 1500 nm or 200 THz [2,3]. Wc discuss strategies how to push the wavelength region of negative refractive index into th visible range by using plasmon resonant metal nanostructures. Importantly, localized plasmon resonances open new design opportunities beyond a straightforward miniaturization of th traditional split ring resonator setup. Low transmission is generally considered to be the majoi drawback of metamaterials containing metallic nanostructures. We show in numerica simulations that two key remedies are now available to overcome major obstacles tha currently limit the development of optical negative-index materials (i) impedance matching designs are capable to suppress high reflectance, and (ii) gain materials embedded in metallic nanostructures can fully compensate for absorptive losses while still retaining the negativ refractive index. The extraordinary nonlinear optical properties of negative-index metamaterials are also discussed [4].

© 2006 Optical Society of America