Question

what do u mean by refraction? and refractive index??​

Answer 1

A refractive index of zero implies that light enters a state of quasi-infinite phase velocity and infinite wavelength. It also means that every point within the metamaterial experiences a quasi-uniform phase of the light wave present, as though all the dipoles inside the metamaterial are oscillating in unison.

Answer 2

Refraction

• The refraction of a wave travelling from one medium to another or from a gradual change in the medium is defined as a shift in the direction of the wave.
• Although light refraction is the most well-known phenomena, refraction also occurs in other waves such as sound and water waves.
• The beginning direction of wave propagation relative to the direction of change in speed determines how much a wave is refracted.

Refractive index

• The refractive index of a substance (also known as the refraction index or index of refraction) is a dimensionless quantity that specifies how quickly light passes through it.
• Its meaning is as follows:

• $n=\frac{c}{v}$

Where

n = refractive index

{c} = speed of light

{v} = phase velocity of light