whats the most powerful wavelength?

[thesk8nmidget]

not just for shows,

i am having a discussion with a friend aboout how he thinks some blue laser is more powerful that a red of equal power with cutting power.

i guess his karate instructor that supposedly works for the university of oregon told him a few years back that from a football field length away a blue laser of equal power to a red laser the blue would cut through more metal.

i thought higher numbered wavelengths (1000nm+) were stronger than (less than 400nm) of equal power.


anyways its a weird question but im sure one of you can give me a good explanation oh which wavelength packs more power.


thanks and good morning.

[Laserman532]

If 1 watt of blue and 1 watt of red were as close to similar design as possible and If both of the lasers are tem00 mode and had exactly the same beam characteristics the blue laser could be focused to a tighter spot due to its shorter wavelength which would produce more power per unit area.

your question as asked can not be answered IMHO.

Im sure Mixedgas or Frothy could phrase it better than I.

[thesk8nmidget]

thank you kind sir! that makes sense i guess.
i mean if you break it down to the common diodes 405nm (blu ray burners) can burn a disc better than a 660nm dvd burner.

and thats because it can be focused in.

thanks for the input

[dstar]

short wavelength - more energy/photon


edit:

look here - the first tab , but it is in german:
http://de.wikipedia.org/wiki/Licht

[ElektroFreak]

In my own personal experience, what laserman said is factual. My blu-ray lasers all burn MUCH better than any of the others, and their burning ability is less dependent on the color of the object being burned. I also remember reading something about how short-wavelength photons have more energy that longer wavelengths, but I don't know the details of that.

[tocket]

What matters when you're trying to burn/cut something is simply absorbed power per area. The wavelength does however have an effect on both of those factors. A short wavelength means that the beam can be focused into a smaller spot.

If we assume that two beams of different wavelengths have the same radiant flux (power/area), the irradiance is indeed the same for both beams, but the absorbed power may not be. This is because every material has its unique absorption spectrum. Any irradiance that is not absorbed is useless if you're trying to cut something! Now, this is where the wavelength becomes interesting again. Anyone who has tried sticking his finger in the beam of a 100 mW red laser knows that this is completely harmless. Doing the same trick with a violet laser will be an almost instantly painful experience. Why? Skin does not absorb red light, but it does absorb violet light. This is also true for many more materials. It is in fact far easier to absorb light of shorter wavelengths, so this is true for most materials. However, as you get into the IR region of the spectrum absorbtion will go up again. Materials that don't absorb any visible light can be excellent IR absorbers.

In conclusion: Shorter wavelengths are generally better for cutting/burning materials, because they can be focused into a smaller spot. However, a longer wavelength may be superior in a certain case, depending on the target material's absorption spectrum.

[heroic]

I think what Tocket is saying is that it depends what colour the object is.

[tocket]

The color is only relevant for lasers in the visible region. A UV, IR or microwave laser does not care about color.

[heroic]

The color is only relevant for lasers in the visible region. A UV, IR or microwave laser does not care about color.

I speak of "colour" as a physicist; UV has colour, as does IR. Even microwave has reflectance that varies with frequency...

[Laserman532]

I speak of "colour" as a physicist; UV has colour, as does IR. Even microwave has reflectance that varies with frequency...

Well then, how long is a piece of string and who can throw it the farthest and would it make any noise if it never lands?

The OP question was vague at best and too many variables to answer correctly.