Luminescence: Difference between revisions
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For context, [[incandescence]] is light from being at high temperature, like [[black-body radiation]] or [[fire]]. | For context, [[incandescence]] is light from being at high temperature, like [[black-body radiation]] or [[fire]]. | ||
'''Luminescence''' then is emission of light that comes from roughly anything | '''Luminescence''' then is emission of light that comes from, well, roughly anything other than being at high temperature. | ||
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* '''Photoluminescence''' - is light that is emitted due to absorption of photons (of a different wavelenth). Basically two variants: | * '''Photoluminescence''' - is light that is emitted due to absorption of photons (of a different wavelenth). Basically two variants: | ||
: '''fluorescence''' | : '''fluorescence''' | ||
:: will absorb light, and emit it at a higher wavelength | :: will absorb light (of varied wavelengths), and emit it at a higher wavelength | ||
:: will stop glowing almost immediately | :: will stop glowing almost immediately - so you usually won't notice it | ||
:: Examples: | :: Examples: | ||
::: happens a bunch in nature | ::: happens a bunch in nature | ||
::: 'optical brightener' detegents | ::: 'optical brightener' detegents | ||
::: tonic water in reaction to UV, due to quinine | ::: more selective to UV: | ||
::: banknotes often have security features to check | :::: tonic water in reaction to UV, due to quinine | ||
:::: banknotes often have security features to check | |||
: '''Phosphorescence''' (actually two different mechanisms) | : '''Phosphorescence''' (actually two different mechanisms) | ||
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* '''Chemiluminescence'''[https://en.wikipedia.org/wiki/Chemiluminescence] - light that comes from a chemical reaction | * '''Chemiluminescence'''[https://en.wikipedia.org/wiki/Chemiluminescence] - light that comes from a chemical reaction | ||
: For example, | : For example, | ||
:: '''[https://en.wikipedia.org/wiki/Luminol luminol]''' | :: '''[https://en.wikipedia.org/wiki/Luminol luminol]''' plus an oxidizing agent makes light. | ||
::: school demonstrations with it will use hydrogen peroxide for a strong and dramatic effect | ::: school demonstrations with it will use hydrogen peroxide for a strong and dramatic effect | ||
::: you may recognize the name from TV series with crime scenes. Blood is an oxidizing agent, you can detect trace amounts of blood (in a dark room, faintly, within the first 30 seconds of spraying. TV exaggerates this a lot.) | ::: you may recognize the name from TV series with crime scenes. Blood is an oxidizing agent, you can detect trace amounts of blood (in a dark room, faintly, within the first 30 seconds of spraying. TV exaggerates this a lot.) | ||
Revision as of 00:16, 8 January 2024
✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.
(Not to be confused with luminance, a descriptive 'amount of light' term that lives in the area of illuminance, luminance, brightness)
Types of luminescence
✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.