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05-13-2008, 05:19 PM #1
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pwnstar
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Waveleangth in relation to energy

Im finishing up my senior year of high school and today my chem teacher started talking about waveleangth, frequncy, amplatude and its relation to energy. Its good the forum taught me most of this already, it should be a easy week

I wana share alittle of todays lesson and also refresh my memory =P lol
http://micro.magnet.fsu.edu/primer/java/wavebasics/

Lower the wavleanth the higher the frequency
Higher the frequncy the Higher the energy
So higher the energy the more burning you get out of your laser. That made sence because people are poping ballons with there ps3 bluray pointers.
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05-13-2008, 11:49 PM #2
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styropyro
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Re: Waveleangth in relation to energy

On Spectra a few people were discussing this, this is a pretty interesting topic.

According to my calculations the energy per photon of the 405nm wavelength is 4.90 x 10^-19 Joules, while the energy per photon of 650nm is only 3.06 x 10 ^ -19 Joules. I think this might explain why we are getting more burning out of our blu-rays.
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05-14-2008, 12:03 AM #3
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usakicksass
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Re: Waveleangth in relation to energy

Look at the big brain on Styropyro!
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05-14-2008, 02:22 AM #4
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Murudai
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Re: Waveleangth in relation to energy

Quote:
 Originally Posted by styropyro According to my calculations the energy per photon of the 405nm wavelength is 4.90 x 10^-19 Joules, while the energy per photon of 650nm is only 3.06 x 10 ^ -19 Joules. I think this might explain why we are getting more burning out of our blu-rays.
To my knowledge that is correct. However, in a blu-ray less photons are actually released compared to a red laser. So in blu-ray they have more energy, but there are less, and in a red they have less power but more photons are put out.

So overall, a blu-ray and red diode of the same mW will put out the same amount of energy. Thus in theory, burning potential is the same.

05-14-2008, 02:31 AM #5
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styropyro
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Re: Waveleangth in relation to energy

Quote:
 Originally Posted by Murudai [quote author=styropyro link=1210699141/0#1 date=1210722579] According to my calculations the energy per photon of the 405nm wavelength is 4.90 x 10^-19 Joules, while the energy per photon of 650nm is only 3.06 x 10 ^ -19 Joules. I think this might explain why we are getting more burning out of our blu-rays.
To my knowledge that is correct. However, in a blu-ray less photons are actually released compared to a red laser. So in blu-ray they have more energy, but there are less, and in a red they have less power but more photons are put out.

So overall, a blu-ray and red diode of the same mW will put out the same amount of energy. Thus in theory, burning potential is the same.
[/quote]
Even if they put out the same amount of total energy, the fewer photons from the blu-ray will have more &quot;knocking&quot; power, by that I mean that they can bump electrons much easier than say red. To try to descibe what I am saying, let's assume that 20 flying pellets from a shotgun have the same energy as 500 flying Airsoft BBs from a cheap airsoft gun. If you blast somebody with 500 Airsoft BBs at once, it is going to hurt, but it won't do much damage. Now if you shoot someone with the 20 flying shotgun pellets, it is most likely going to penetrate into your victim and do much more damage than airsoft BBs, even though they have the same total energy. This could have something to do with why Blu-ray burns so much better.

This also explains why 5mW of 405nm will make GITD stuff glow while 200mW of 660nm will barely do anything to GITD items.

Anybody please correct me if any of this is incorrect.
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05-14-2008, 02:47 AM #6
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Re: Waveleangth in relation to energy

Quote:
 Originally Posted by styropyro This also explains why 5mW of 405nm will make GITD stuff glow while 200mW of 660nm will barely do anything to GITD items. Anybody please correct me if any of this is incorrect.
That sounds about right. You need a certain amount of energy to knock electrons up to the next energy level, and a 405nm is better able to do that than a 650nm, so you get fluorescence as the electrons release energy and drop back to ground state.

But burning is different, as that's about generating overall heat energy rather than knocking electrons around. If the same bit of material absorbs 405nm and 650nm light equally, then in theory you will have the same burning power if you have the same energy output from the 405nm and the 650nm.

This really is something for a laboratory to test, rather than us speculating

05-14-2008, 02:56 AM #7
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pwnstar
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Re: Waveleangth in relation to energy

Quote:
 Originally Posted by styropyro [quote author=Murudai link=1210699141/0#3 date=1210731744][quote author=styropyro link=1210699141/0#1 date=1210722579] According to my calculations the energy per photon of the 405nm wavelength is 4.90 x 10^-19 Joules, while the energy per photon of 650nm is only 3.06 x 10 ^ -19 Joules. I think this might explain why we are getting more burning out of our blu-rays.
To my knowledge that is correct. However, in a blu-ray less photons are actually released compared to a red laser. So in blu-ray they have more energy, but there are less, and in a red they have less power but more photons are put out.

So overall, a blu-ray and red diode of the same mW will put out the same amount of energy. Thus in theory, burning potential is the same.
[/quote]
Even if they put out the same amount of total energy, the fewer photons from the blu-ray will have more &quot;knocking&quot; power, by that I mean that they can bump electrons much easier than say red. To try to descibe what I am saying, let's assume that 20 flying pellets from a shotgun have the same energy as 500 flying Airsoft BBs from a cheap airsoft gun. If you blast somebody with 500 Airsoft BBs at once, it is going to hurt, but it won't do much damage. Now if you shoot someone with the 20 flying shotgun pellets, it is most likely going to penetrate into your victim and do much more damage than airsoft BBs, even though they have the same total energy. This could have something to do with why Blu-ray burns so much better.

This also explains why 5mW of 405nm will make GITD stuff glow while 200mW of 660nm will barely do anything to GITD items.

Anybody please correct me if any of this is incorrect.[/quote]

yea that seems exactly right. I used to hear that &quot;red burns better cause its a darker color.&quot; but that cant really be true.

05-14-2008, 03:02 AM #8
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Re: Waveleangth in relation to energy

It depends on what you are shooting. If the thing you are shooting is absorbing 100 percent of the light it doesnt matter if it is 405 nm of 10600 nm, the power put in will be the same so the burning will be the same as murudai said above. Higher energy photons will do different things (see photoelectric effect), but for burning that shouldnt really contribute. When you are burning things if the blue one works better it is likely entirely due to the material you are shooting absorbing more at 405nm than at 650nm.

While the shotgun example works well for BBs and pellets, it doesnt really reflect how energy from waves is absorbed. While photons are a nice convenient way of summing up the energy quantization of electromagnetic radiation, absorption of light can be described pretty much entirely classically by a damped oscillator assuming that no ionization is taking place. At 650 nm you have about 2 eV photons so nothing will be ionized, at 405 you have 3 eV photons which is still below the ionization potential of everything other than alkali earth metals, and Im pretty confident you arent burning those.

05-14-2008, 09:23 PM #9
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Re: Waveleangth in relation to energy

can't blu be focused better.
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05-14-2008, 09:30 PM #10
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Re: Waveleangth in relation to energy

Quote:
 Originally Posted by jamilm9 can't blu be focused better.
I've heard that, but even if it can be focused to a smaller dot, it would be too hard to find the EXACT focal point, your heartbeat going through your fingers holding the laser against a flat surface would be enough to set the focal point off :P

So, what is it that is making blu-rays burn so much better than other lasers? We HAVE to figure this one out!
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