A report onWavelength and Refractive index

The refractive index can be seen as the factor by which the speed and the wavelength of the radiation are reduced with respect to their vacuum values: the speed of light in a medium is v = c/n, and similarly the wavelength in that medium is λ = λ0/n, where λ0 is the wavelength of that light in vacuum.

- Refractive index

For electromagnetic waves the speed in a medium is governed by its refractive index according to

- Wavelength

Refraction

Redirection of a wave as it passes from one medium to another.

Redirection of a wave as it passes from one medium to another.

For light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle of incidence θ1 and angle of refraction θ2 is equal to the ratio of phase velocities (v1 / v2) in the two media, or equivalently, to the refractive indices (n2 / n1) of the two media.

The refractive index of materials varies with the wavelength of light, and thus the angle of the refraction also varies correspondingly.

Dispersion (optics)

Phenomenon in which the phase velocity of a wave depends on its frequency; sometimes the term chromatic dispersion is used for specificity to optics in particular.

Phenomenon in which the phase velocity of a wave depends on its frequency; sometimes the term chromatic dispersion is used for specificity to optics in particular.

The most familiar example of dispersion is probably a rainbow, in which dispersion causes the spatial separation of a white light into components of different wavelengths (different colors).

Most often, chromatic dispersion refers to bulk material dispersion, that is, the change in refractive index with optical frequency.

Optical fiber

Flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair.

Flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair.

Optical fibers typically include a core surrounded by a transparent cladding material with a lower index of refraction.

Optical fibers can be used as sensors to measure strain, temperature, pressure, and other quantities by modifying a fiber so that the property being measured modulates the intensity, phase, polarization, wavelength, or transit time of light in the fiber.

Light

Electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye.

Electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye.

Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths).

where θ1 is the angle between the ray and the surface normal in the first medium, θ2 is the angle between the ray and the surface normal in the second medium and n1 and n2 are the indices of refraction, n = 1 in a vacuum and n > 1 in a transparent substance.

Numerical aperture

[[Image:Numerical aperture.svg|thumb|The numerical aperture with respect to a point

[[Image:Numerical aperture.svg|thumb|The numerical aperture with respect to a point

By incorporating index of refraction in its definition, NA has the property that it is constant for a beam as it goes from one material to another, provided there is no refractive power at the interface.

is the wavelength of the light.

Wave

Propagating dynamic disturbance of one or more quantities.

Propagating dynamic disturbance of one or more quantities.

Electromagnetic waves, according to their frequencies (or wavelengths) have more specific designations including radio waves, infrared radiation, terahertz waves, visible light, ultraviolet radiation, X-rays and gamma rays.

A material which absorbs a wave's energy, either in transmission or reflection, is characterized by a refractive index which is complex.

Superlens

Lens which uses metamaterials to go beyond the diffraction limit.

Lens which uses metamaterials to go beyond the diffraction limit.

Furthermore, the level of feature detail, or image resolution, is limited to a length of a wave of radiation.

Microscopy takes into account parameters such as lens aperture, distance from the object to the lens, and the refractive index of the observed material.