Dispersion (optics)

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Optical dispersion is the dependence of a material's refractive index on the frequency or wavelength of light. Different spectral components therefore travel at different phase velocities and are refracted by different amounts.

A prism separates white light into colours because shorter and longer wavelengths bend differently. Rainbows arise from dispersion combined with refraction and reflection in water droplets.

Normal dispersion usually means the refractive index decreases as wavelength increases, while anomalous dispersion can occur near absorption bands. Dispersion also causes pulses to broaden as their frequency components travel at different group velocities.

The effect is important in lenses, fibre-optic communication, spectroscopy, lasers, atmospheric optics, and material characterisation. Optical systems often use combinations of materials to reduce unwanted chromatic aberration or pulse distortion.

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• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Dispersion_(optics)