Hyperbolic-polaritons-enabled dark-field lens for sensitive detection.

Sensitive detection of features in a nanostructure may sometimes be puzzled in the presence of significant background noise. In this regard, background suppression and super-resolution are substantively important for detecting weakly scattering nanoscale features. Here, we present a lens design, termed hyperbolic-polaritons-enabled dark-field lens (HPEDL), which has the ability to accomplish straightforward sensitive detection. This HPEDL structure consists of type I and type II hyperbolic media that support high-k field waves via hyperbolic polaritons (HPs). We show that the cone-like characteristics of the HPs could be manipulated while the influence of the low-k field waves would be removed. Numerical simulations demonstrate that this proposed structure can successfully realize straightforward sensitive detection by modifying its thickness under the phase compensation condition. Besides, the minimum resolvable length and angular-dependent performance for sensitive detection are also demonstrated by simulations. Remarkably, these findings are very promising for propelling nanophotonics technologies and constitute a further important step towards practical applications of optical microscopy.