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You can buy white light sources from:
- EXALOS: superluminescent light-emitting diodes (SLED), with emission wavelengths between 650 and 1700 nm, high output power and broad optical bandwidth, speckle free, suited for optical coherence tomography, fiber-optic gyroscopes and fiber-optic sensors
Ask RP Photonics for advice concerning various kinds of white light sources (e.g. superluminescent sources and fiber ASE sources) or about their applications.
Definition: light sources with very broad optical bandwidth
A white light source is a light source with a broad optical bandwidth (usually 100 nm or more). However, two different meanings of the term are in use:
- In some cases, a light source really emits visible white light. Such sources are required e.g. for lighting applications and for colorimetry. They may contain something such as a bulb (e.g. a tungsten-halogen lamp), emitting a smooth and very broadband optical spectrum. Spectra of fluorescent lamps or other gas discharge lamps (e.g. xenon lamps) can also look white but are much more structured.
- In other cases, a broadband light source is meant, which does not necessarily emit in the visible spectral region. Such sources can be superluminescent sources, e.g. superluminescent diodes, and typically exhibit a high spatial coherence, whereas the temporal coherence is low according to the large bandwidth. Typical applications of this kind of white light sources are white light interferometry, characterization of optical components, and spectroscopy.
- Supercontinuum generation is a method for obtaining even broader spectra. It is based on strongly nonlinear interactions e.g. in an optical fiber.
For some applications, the bandwidth specified as a full-width half-maximum value is important, whereas weak tails in the spectrum are not relevant. In other cases, it is only important to have some level of power spectral density over a broad range, even if the power spectral density varies a lot within that range.
See also: bandwidth, supercontinuum generation, white light interferometers, interferometers, superluminescent sources, amplified spontaneous emission
Since October 2008, the Encyclopedia of Laser Physics and Technology is also available in the form of a two-volume book. Maybe you would enjoy reading it also in that form! The print version has a carefully designed layout and can be considered a must-have for any institute library, laser research group, or laser company.
You may order the print version via Wiley-VCH.
