Silver Film Points to Superlenses

A team of engineers at the University of California, Los Angeles, has demonstrated the regeneration of evanescent waves by the excitation of surface plasmons in a film with a negative dielectric constant. Reporting in the April 7 issue of Optics Express, the group suggests that the effect may be useful in the realization of "superlenses" for far-field The researchers fabricated the reversed attenuated total reflection optical component by depositing a 50-nm-thick film of silver on the flat surface of a semispherical BK 7 prism. They illuminated the center of the setup with 351.1- to 514.5-nm radiation from an argon-ion laser and imaged the response using a CCD camera positioned 5 cm from the prism.