Uploaded June 2024 | Updated September 2026, 22 minutes ago
Chromatic dispersion is the wavelength dependent speed in a material.
The refractive index ('n') of a material is defined by the speed of light in a vacuum divided by the speed or 'phase velocity' of light in that material. However, different wavelengths will have slightly differing indices of refraction, leading to a wavelength dependent speed, otherwise known as chromatic dispersion. The steeper the index vs wavelength curve, the greater the amount of dispersion.
For short light pulses, this can lead to pulse broadening. Since a pulse may contain multiple wavelengths, each wavelength of the pulse travels at a different speed, where difference in the fastest and slowest wavelength lead to broadening effect. This is especially relevant for ultrafast laser, which by design must contain many wavelengths staying in phases.
Dispersion also manifests as a wavelength dependent refraction angle when combined with Snell's law, which is why a prism will separate while light into its spectrum of colors.
Chromatic dispersion is the wavelength dependent speed in a material.
The refractive index ('n') of a material is defined by the speed of light in a vacuum divided by the speed or 'phase velocity' of light in that material. However, different wavelengths will have slightly differing indices of refraction, leading to a wavelength dependent speed, otherwise known as chromatic dispersion. The steeper the index vs wavelength curve, the greater the amount of dispersion.
For short light pulses, this can lead to pulse broadening. Since a pulse may contain multiple wavelengths, each wavelength of the pulse travels at a different speed, where difference in the fastest and slowest wavelength lead to broadening effect. This is especially relevant for ultrafast laser, which by design must contain many wavelengths staying in phases.
Dispersion also manifests as a wavelength dependent refraction angle when combined with Snell's law, which is why a prism will separate while light into its spectrum of colors.
