Fig. 6

Numerical and experimental results of FSL. a, b Transmission properties of a conventional superles and a FSL, respectively. Propagating waves and evanescent waves are represented by black and red line, respectively. While the amplitude of the evanescent waves decay exponentially again after they pass through the conventional superlens, evanescent waves are converted into propagating wave at the exit surface of the FSL, making far-field imaging possible [73]. c A schematic design of the first far-field superlens. It is a periodically corrugated silver slab in a glass substrate designed for a wavelength equal to 376 nm. a = 45 nm, b = 35 nm, c = 55 nm, d = 150 nm [73]. d Simulated electromagnetic density of an object (black) and image plane with (red) and without (blue) the superlens, assuming numerical aperture (NA) is 1.5. Here, an object is composed of two 40 nm lines separated by 40 nm [73]. e Experimental demonstration of the far-field superlens, where an object is a pair of wires with line width of 50 nm and spacing of 70 nm. NA = 1.4, and the wavelength is 377 nm. Top: SEM image of an object. Middle: image without superlens. Bottom: reconstructed FSL image. (Scale bars indicate 200 nm) [75]