Figure 1

(a) Schematic of broadband, planar metallic lens. The top layer is a patterned gold layer of thickness 50 nm and the base layer is of quartz. The propagation vector K₀ is normally incident to the lens, while the direction of E field is normal to K₀. (b) Emission profile at λ = 580 nm along the xz and yz planes. Both graphs are on same color scale. (c) Calculated focal length (f) and focal spot size (w) indicated by “*” using FDTD simulations. The change in focal length was smaller than that of depth of the focus. The depth of focus has been shaded as a guide for eye.