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Bright light therapy is a common treatment for seasonal affective disorder and for circadian rhythm sleep disorders The elderly frequently cite depression as a notable ailment. Many researchers have linked the depression to seasonal affective disorder (SAD), and seasonal mood variations have been linked to lack of light.
In a dispersive prism, material dispersion (a wavelength-dependent refractive index) causes different colors to refract at different angles, splitting white light into a spectrum. A compact fluorescent lamp seen through an Amici prism. Dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. [1]
In optics, a diffuser (also called a light diffuser or optical diffuser) is any material that diffuses or scatters light in some manner to transmit soft light.Diffused light can be easily obtained by reflecting light from a white surface, while more compact diffusers may use translucent material, including ground glass, teflon, opal glass, and greyed glass.
This is a result of the prism material's index of refraction varying with wavelength (dispersion). Generally, longer wavelengths (red) undergo a smaller deviation than shorter wavelengths (blue). The dispersion of white light into colors by a prism led Sir Isaac Newton to conclude that white light consisted of a mixture of different colors.
Light-emitting diode therapy (LEDT) is an therapeutic approach using different wavelengths of LED lights to treat disease. (The diagram is a blue light therapy, 415 nm wavelength) Light-emitting diode therapy (LEDT) is a clinical approach that applies different wavelengths of light to cure diseases or conditions with skin-safe lights.
[1] [2] It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light. The refractive index of most transparent materials decreases with increasing wavelength. [3] Since the focal length of a lens depends on the refractive index, this variation in refractive index affects focusing. [4]
Spectroscopic reflectance of a thin film on a substrate represents the ratio of the intensity of light reflected from the sample to the intensity of incident light, measured over a range of wavelengths, whereas spectroscopic transmittance, T(λ), represents the ratio of the intensity of light transmitted through the sample to the intensity of ...
Circular dichroism causes incident linearly polarized light to become elliptically polarized. The two phenomena are closely related, just as are ordinary absorption and dispersion. If the entire optical rotatory dispersion spectrum is known, the circular dichroism spectrum can be calculated, and vice versa.