Porous rubber microbeads suspended in a gel are found to exhibit a negative acoustic index of refraction, which makes these metamaterials promising for underwater acoustic applications. Figure 1: ...

Among the various sensing modalities available for bioprocess operations, index of refraction (IoR) is intriguing for its simplicity and capability for sample-less, real-time readout. A group led by ...

The refractive index of a material defines the angle through which light is bent when it travels between a material and the vacuum. Ordinary materials such as glass have refractive indices between one ...

Physicists are involved in an unusually heated debate over the reality of a new kind of refraction and about the possibility of making perfect lenses. Edwin Cartlidge reports. If you think science is ...