standard spectral lines (original) (raw)
Author: the photonics expert (RP)
Definition: spectral lines which are often used as wavelength references
general optics- spectral lines
- standard spectral lines
- laser lines
- emission lines
- absorption lines
Related: spectral linesspectral lampswavelengthgas discharge lampslaser lines
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DOI: 10.61835/i46 Cite the article: BibTex BibLaTex plain textHTML Link to this page! LinkedIn
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Contents
What are Standard Spectral Lines?
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 particular 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.
Frequently Asked Questions
This FAQ section was generated with AI based on the article content and has been reviewed by the article’s author (RP).
What are standard spectral lines?
Standard spectral lines are specific, well-defined spectral lines from sources like gas discharge lamps or lasers. They are widely used as precise wavelength references, for example for specifying the refractive index of optical materials.
Why are specific spectral lines used to characterize optical glasses?
The refractive index of an optical glass depends on the wavelength. By specifying the refractive index at a set of standard wavelengths (e.g., the C, d, and F lines), manufacturers can precisely characterize the dispersive properties of their materials.
What are some common sources for standard spectral lines?
Common sources are low-pressure gas discharge lamps containing elements like hydrogen (for the C and F lines), helium (d line), or mercury (e, g, h lines). The red (632.8 nm) and green (543.5 nm) lines from helium–neon lasers are also often used.
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