HiggsBoson
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When I point my laser pointer at any glow in the dark material, it glows very bright and I can write with it, I was wondering how it works?
My laser pointer has a wavelength of 405nm so it's very close to UV.u
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Joinedup
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I guess you've got some phosphorescent material.

How I think it works is that the photons incident on the phosphorescent material excite orbital electrons to a higher energy level, then at a later time the electrons fall back to their original energy level emitting a photon of visible light.

phosphorescent pigment for analogue watches, fire escape signs etc. is optimised to have the emission of the photons delayed by quite a considerable time so it'll continue to glow for a few minutes after being exposed to light - tbh not sure on the detail of how the delay is achieved.

Having mucked around with some fire escape signs at work I think there is a threshold wavelength for incident light to excite the electrons (similar principle to the photoelectric effect) in that you can blast the material with a red laser and get no light emitted after you stop... but it'll emit light strongly after you hit it with a blue LED (built into a poundland cigarette lighter) - so it's evidence for the particle nature of light.

an entirely legitimate use of phosphorescent pigment is making fake radioactive waste spills... like this
https://www.youtube.com/watch?v=WzrR8RT7g8w
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HiggsBoson
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So it's basically what happens in fluorescent tubes?
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Milax1x
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(Original post by HiggsBoson)
So it's basically what happens in fluorescent tubes?
Yeah but it’s mercury vapour that produces the UV light which then interacts with phosphors to produce white light
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HiggsBoson
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Oh OK thank you 😀
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