Encyclopedia > letter S > standard spectral lines

Standard Spectral Lines

Author: the photonics expert Dr. Rüdiger Paschotta (RP)

Definition: spectral lines which are often used as wavelength references

Category: article belongs to category general optics general optics

DOI: 10.61835/i46 Cite the article: BibTex plain text HTML Link to this page LinkedIn

Certain spectral lines – usually from common low-pressure gas discharge lamps used as spectral lamps – are frequently used as wavelength references. There are also laser lines which can fulfill similar purposes.

The refractive indices of optical materials (mostly optical glasses) are often specified at a number of standard wavelengths, in particularly at the lines C, C', D, d, e, F and F' (see Table 1).

Wavelength	Color	Designation	Element
365.0146 nm	ultraviolet	i	mercury
404.6561 nm	violet	h	mercury
435.8328 nm	blue	g	mercury
479.9914 nm	blue	F'	cadmium
486.1327 nm	blue	F	hydrogen
543.5 nm	green	green HeNe	helium–neon laser
546.074 nm	green	e	mercury
587.5618 nm	yellow	d	helium
589.2938 nm	orange	D	sodium
632.8 nm	red	red HeNe	helium–neon laser
643.8469 nm	red	C'	cadmium
656.2725 nm	red	C	hydrogen
706.5188 nm	red	r	helium
852.11 nm	infrared	s	cesium
1013.98 nm	infrared	t	mercury

Table 1: Table of spectral lines which are frequently used in optics.

See the article on laser lines for many more lines generated with lasers.

More to Learn

Encyclopedia articles:

Questions and Comments from Users

Here you can submit questions and comments. As far as they get accepted by the author, they will appear above this paragraph together with the author’s answer. The author will decide on acceptance based on certain criteria. Essentially, the issue must be of sufficiently broad interest.

Please do not enter personal data here. (See also our privacy declaration.) If you wish to receive personal feedback or consultancy from the author, please contact him, e.g. via e-mail.

By submitting the information, you give your consent to the potential publication of your inputs on our website according to our rules. (If you later retract your consent, we will delete those inputs.) As your inputs are first reviewed by the author, they may be published with some delay.