Nano-Optical Superlenses with Negative-Index Sandip Tiwari, Cornell U Metamaterials
We have demonstrated experimentally the imaging at 1.55 µm wavelength by a generalized photonic crystal superlens (Fig. 1) nanofabricated in InGaAsP/InP heterostructure. By designing a suitable lens surface termination, an image spot size of 0.122 was achieved, demonstrating superlens imaging with sub-wavelength resolution well below the diffraction limit (0.52).

We have created a new nano-optical microlens that focuses infrared light at telecommunication frequencies. The two-dimensional metamaterial microlens, which uses the negative refractive index, was created by nano-engineering a photonic-crystal substrate into a multi-layered semiconducting wafer. The focusing power of this microlens sets a world record for one of the shortest focal lengths ever achieved, focusing the infrared beam to a spot just 12 microns away from the surface— at the limit of diffraction laws. In addition, the location of the focused light image was very sharp with little blurring. This represents a significant advance in light imaging technology and has the potential to lead to innovations in high density imaging systems.