(color online) Spherical hyperlens. (a) Schematic of spherical hyperlens comprised of 9 pairs of Ag and Ti₃O₅ layers. (b) Cross section of spherical hyperlens along green incident plane. The object with sub-wavelength features is carved in Cr layer atop Ag–Ti₃O₅ multilayer (also shown in light blue in (a)). TM component of unpolarized light relative to the plane is labelled by K. (c) Comparison between isofrequency contours for TM modes in hyperlens and isotropic medium made of silicon oxide. Arrows, which are of unit length and on ultra-flat curve, show that all the k components (including those much larger than the wave vectors available in dielectrics) propagate along the same radial direction, indicating the lack of diffraction. (d) SEM image of three dots positioned triangularly with gaps of 180 nm, 170 nm, and 160 nm. (e) Image and (f) intensity versus distance on cross section of the object along red line after being magnified. Reproduced with permission from Ref. [30].