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awlego 02-10-2010 10:02 PM

Fluorescing with 532nm
 
I have a pink highlighter, and when I shine my green 532nm laser on the case, it glows a nice yellow. Not only is the dot yellow, but it throws off a yellow glow to everything around it. At most other objects, the dot may change brightness, or even color a little bit, but the scatter around the object is still green. Has anybody else experienced this? I believe that it is actually flourescing with the 532nm light... can anyone confirm/deny this?

-Awlego

roosl 02-10-2010 10:31 PM

Re: Fluorescing with 532nm
 
Yes, in fact I had fun noticing that when I'd hit some red ornaments on my Christmas tree, they (and the dot) would glow yellow. Others, even though to my eye they seemed the same red, would not. Same thing happens when I hit a pink post-it note.

rpaloalto 02-10-2010 11:38 PM

Re: Fluorescing with 532nm
 
Edit?
I just now noticed you were talking about 532nm green

I noticed this too with highlighter ink. I actually have a little yellow smiley face drawn on my celling. The neat thing about it is you cant see it unless you shine some 405nm on it:)

RA_pierce 02-10-2010 11:54 PM

Re: Fluorescing with 532nm
 
Quote:

Originally Posted by awlego (Post 653900)
I have a pink highlighter, and when I shine my green 532nm laser on the case, it glows a nice yellow. Not only is the dot yellow, but it throws off a yellow glow to everything around it. At most other objects, the dot may change brightness, or even color a little bit, but the scatter around the object is still green. Has anybody else experienced this? I believe that it is actually flourescing with the 532nm light... can anyone confirm/deny this?

-Awlego


I'm surprised that it's not common knowledge that green lasers can make objects fluoresce, since most of us here own at least one greenie.

When a photon of the right wavelength is absorbed by an electron, the extra energy can "bump" or "excite" the electron into a higher energy state. This is only temporary, and the electron will release that extra energy as another photon. The emitted photon's energy is equivalent to the difference in energy applied and energy absorbed. Energy is lost as heat and as vibrations in the particle, so the wavelength of the emitted photon is longer (less energetic) than the photon absorbed. However, this is not always the case. In some instances two photons can be absorbed, in which case a single photon of higher energy may be emitted.

Violet/UV light is NOT the only light that can cause fluorescence.

Fluorescence is similar to stimulated emission (lasers) and phosphorescence (aka glow-in-the-dark) in that a photon must act on a molecule which causes the molecule to emit another photon... but there are differences.

awlego 02-11-2010 03:38 AM

Re: Fluorescing with 532nm
 
I guess in the back of my mind I did know that other wavelengths could cause fluorescence, but I just thought it was cool as UV is what I normally think of causing things to glow :)

Thanks for the feedback!

scopeguy20 02-11-2010 05:35 AM

Re: Fluorescing with 532nm
 
Shine a Greenie on a ruby! they glow very bright especially the synthetic ones, watch out for reflections though! -Glenn

nikokapo 02-11-2010 03:04 PM

Re: Fluorescing with 532nm
 
Quote:

Originally Posted by RA_pierce (Post 653971)
I'm surprised that it's not common knowledge that green lasers can make objects fluoresce, since most of us here own at least one greenie.

When a photon of the right wavelength is absorbed by an electron, the extra energy can "bump" or "excite" the electron into a higher energy state. This is only temporary, and the electron will release that extra energy as another photon. The emitted photon's energy is equivalent to the difference in energy applied and energy absorbed. Energy is lost as heat and as vibrations in the particle, so the wavelength of the emitted photon is longer (less energetic) than the photon absorbed. However, this is not always the case. In some instances two photons can be absorbed, in which case a single photon of higher energy may be emitted.

Violet/UV light is NOT the only light that can cause fluorescence.

Fluorescence is similar to stimulated emission (lasers) and phosphorescence (aka glow-in-the-dark) in that a photon must act on a molecule which causes the molecule to emit another photon... but there are differences.



This ^


Also, try it with an orange highlighter, works as well :)

ohada 02-11-2010 10:32 PM

Re: Fluorescing with 532nm
 
Here are a couple materials I have that shine a very nice red when hit with 532nm green laser.

First is a lovely synthetic ruby that fluoresces very brightly, then a green laser target which contains a phosphorescent material (keeps shining red after laser is gone up to 5 minutes!) which is composed of Europium doped Strontium Salt (both of them from eBay, not expensive at all).

http://i497.photobucket.com/albums/r...a/DSC_0318.jpg
http://i497.photobucket.com/albums/r...a/DSC_0329.jpg
http://i497.photobucket.com/albums/r...a/DSC_0341.jpg
http://i497.photobucket.com/albums/r...a/DSC_0342.jpg
http://i497.photobucket.com/albums/r...a/DSC_0345.jpg


http://i497.photobucket.com/albums/r...a/DSC_0346.jpg
http://i497.photobucket.com/albums/r...a/DSC_0350.jpg
http://i497.photobucket.com/albums/r...a/DSC_0351.jpg
http://i497.photobucket.com/albums/r...a/DSC_0352.jpg

Both of them look even more amazing in a dark room, but I couldn't capture that with my camera,

Ohad

Woodofcville 02-11-2010 10:57 PM

Re: Fluorescing with 532nm
 
^thats cool! I have noticed this with an orange piece of paper.

pullbangdead 02-12-2010 01:33 AM

Re: Fluorescing with 532nm
 
Quote:

Originally Posted by RA_pierce (Post 653971)
When a photon of the right wavelength is absorbed by an electron, the extra energy can "bump" or "excite" the electron into a higher energy state. This is only temporary, and the electron will release that extra energy as another photon.

Correct.

Quote:

Originally Posted by RA_pierce (Post 653971)
The emitted photon's energy is equivalent to the difference in energy applied and energy absorbed. Energy is lost as heat and as vibrations in the particle, so the wavelength of the emitted photon is longer (less energetic) than the photon absorbed.

Close, but not quite. The wavelength of the emitted photon is entirely decided by the material, NOT by the wavelength of the original photon (as long as the original photon is low enough wavelength to achieve fluorescence of course, but if it wasn't we wouldn't be having the conversation). The original photon excites an electron into a higher energy state. This could be across a bandgap as in the case of a semiconductor, or it could be between orbitals in individual atoms like is the case in doped glass, where you are exciting electrons around individual atoms (but many of them).

The electron absorbs all the energy of the photon, and goes up to a level with that energy. In a semiconductor that fluoresces, as long as there is enough energy to get up into the conduction band across the bandgap, then it'll land in the CB at the same energy level as the energy it absorbed from the photon. If the photon doesn't have enough energy to get into the conduction band, then the photon won't be absorbed and we wouldn't be having this conversation). Once an electron is in the CB, it'll fall in energy back down close to the bottom of the conduction band by other mechanisms (heat, etc). Then it'll fall back down to the valence band, through the bandgap, giving off a photon. But you see, the photon wavelength/energy then corresponds to the bandgap, not how much energy went in. All the energy got absorbed, but the ligth was determined by the bandgap of the material, nothing else.

The same happens with things like glass, except instead of bands, you have individual orbitals at precise energies. So the wavelength emitted corresponds directly to the orbital energies present in the material, and has nothing to do with the wavelength of the incident light (once more, as long as the light has at least the minimum energy to get an electron into a higher orbital).

Make sense?

Quote:

Originally Posted by RA_pierce (Post 653971)
In some instances two photons can be absorbed, in which case a single photon of higher energy may be emitted.

Violet/UV light is NOT the only light that can cause fluorescence.

Fluorescence is similar to stimulated emission (lasers) and phosphorescence (aka glow-in-the-dark) in that a photon must act on a molecule which causes the molecule to emit another photon... but there are differences.

Correct. Phosphorescence is just slow fluorescence, and stimulated emission is just the counterpart to the stimulated absorption that allows for fluorescence and phosphorescence both to exist.

As long as the energy of a photon is high enough to get absorption across the gap/orbitals/whatever, then the light can cause fluorescence, so any color higher in wavelength is "fluorescable" by a given laser.

awlego 02-12-2010 02:07 AM

Re: Fluorescing with 532nm
 
So that's why things like bright orange paper or highlighters achieve such a unique color, because they are not only reflecting light, but actually fluorescing too?

pullbangdead 02-12-2010 02:45 AM

Re: Fluorescing with 532nm
 
Quote:

Originally Posted by awlego (Post 654726)
So that's why things like bright orange paper or highlighters achieve such a unique color, because they are not only reflecting light, but actually fluorescing too?

The "color" of an object comes from several factors. Reflection and absorption are the most common ways that a things "color" is decided, but fluorescence also comes into it as well. Many products use fluorescence to make more desirable colors. White paper and laundry detergents come to mind as the things that most commonly use fluorescence to make a more appealing color.

Laundry detergents not only preserve the absorbing/reflecting dyes that give clothing color, they often add UV brighteners to literally make your clothes glow in the sunlight, to make them literally brighter. They literally make your clothes fluoresce, making your clothes look better.

RA_pierce 02-12-2010 08:33 PM

Re: Fluorescing with 532nm
 
Thanks for the correction, pbd.
It does make sense.
:thanks:

Cyparagon 02-12-2010 11:00 PM

Re: Fluorescing with 532nm
 
Quote:

Originally Posted by pullbangdead (Post 654750)
White paper and laundry detergents come to mind as the things that most commonly use fluorescence to make a more appealing color.

Don't forget highlighters. With the fluorescent dye, it appears brighter orange because not only is it reflecting the orange (or whatever color) but also higher wavelengths converted to orange.

hakzaw1 02-12-2010 11:06 PM

Re: Fluorescing with 532nm
 
Quote:

Originally Posted by scopeguy20 (Post 654198)
Shine a Greenie on a ruby! they glow very bright especially the synthetic ones, watch out for reflections though! -Glenn

Please send me a ruby- either kind- I want to see this for myself--I promise to send it back!!!!! J/K--hz

scopeguy20 02-13-2010 04:50 PM

Re: Fluorescing with 532nm
 
That's a pretty big synthetic ruby Ohad! Nice pics! T/Y for posting, +1 rep -Glenn


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