Multiband negative refraction in one-dimensional photonic crystals.

We simulate a lossless one-dimensional photonic crystals (1DPC) structure and show that negative refraction could be present near the low frequency edge of at least the second, fourth and sixth bandgaps. We experimentally demonstrate for the first time negative refraction in strongly modulated porous silicon 1D-PC in the visible and near infrared regions. This 1D-PC structure may allow the realization of short-focus Veselago lenses in different optical bands. An advantage of our structure is its simplicity allowing for cheap and rapid fabrication of samples.