  Plasmonics has conventionally been in the realm of metal-optics. However,
conventional metals as plasmonic elements in the near-infrared (NIR) and
visible spectral ranges suffer from problems such as large losses and
incompatibility with semiconductor technology. Replacing metals with
semiconductors can alleviate these problems if only semiconductors could
exhibit negative real permittivity. Aluminum doped zinc oxide (AZO) is a low
loss semiconductor that can show negative real permittivity in the NIR. A
comparative assessment of AZO-based plasmonic devices such as superlens and
hyperlens with their metal-based counterparts shows that AZO-based devices
significantly outperform at a wavelength of 1.55 um. This provides a strong
stimulus in turning to semiconductor plasmonics at the telecommunication
wavelengths.
