  Noble metals such as gold and silver are the primary metallic building blocks
of metamaterial devices. Making subwavelength-sized structural elements from
these metals seriously limits the optical performance of a device, however, and
complicates the manufacturing process of nearly all metamaterial devices in the
optical wavelength range. As an alternative to noble metals, we propose to use
heavily-doped oxide semiconductors that offer both functional and fabrication
advantages in the near-infrared. In this letter, we report an experimental
demonstration of negative refraction in a near-infrared metamaterial device
that is designed and fabricated using aluminum-doped zinc oxide.
