Light is refracted when it enters a material like water or glass. Depending on the density of the material, light will reduce in speed as it travels through, causing it to change direction.

THE birefringence of many organic crystals of the aromatic class is large, and when the intermediate index differs widely from the upper and lower indexes, the angles of internal and external ...

For the first time, scientists have demonstrated that negative refraction can be achieved using atomic arrays—without the need for artificially manufactured metamaterials. Scientists have long ...