Diffractive nanoslit lenses for subwavelength focusing

Creating a subwavelength focus spot from nanoslits becomes possible when diffraction occurs inside strongly anisotropic materials with hyperbolic dispersion. In this work, we study diffraction from nanoslits and numerically show that the interference patterns could be smaller than λ/10. The designs studied in this work are feasible with current nanofabrication techniques. We also review our recent work on metal nanoslit lenses, which behave as conventional convex or concave dielectric lenses depending on the linear polarization of incident light.