Focusing effect of photonic crystal concave lenses made from porous dielectrics

Efficient focusing with a concave lens b

Efficient focusing with a concave lens based on a photonic crystal with an unusual effective index of refraction

✍ Foca, E. ;Föll, H. ;Daschner, F. ;Sergentu, V. V. ;Carstensen, J. ;Frey, S. ;Knö 📂 Article 📅 2005 🏛 John Wiley and Sons 🌐 English ⚖ 152 KB

## Abstract This work reports measurements with a concave lens based on a photonic crystal (PC) structure, which was designed to have an effective index of refraction __n__~eff~ < 1 or even < 0, and which is intended as a model system for future down‐scaled optical elements based on PCs with an un