What is refractive index less than 1?

Refractive index less than 1 refers to substances that have a refractive index value below 1. It is a unique property found in some materials and is often associated with anomalous dispersion. This phenomenon occurs when the refractive index of a material decreases as the frequency or wavelength of light increases.

Substances that exhibit refractive index less than 1 include certain types of liquids and gases, which typically have a lower density than air. This can lead to some interesting phenomena, such as a straw appearing bent when placed in a glass of water.

One important application of refractive index less than 1 is in the design of optical fibers, which are used for communication over long distance. By using materials with a lower refractive index, light can be transmitted more efficiently and with less loss.

Overall, while refractive index less than 1 is not a common property, it is an important area of study for scientists and engineers working in the field of optics and materials science.