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How does a 1 mW laser burn?

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How does it burn when i have got a 10mw laser that can't burn? Is it the colour or something else?
 





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a 1mw laser can only burn if you pour gas on it and set it on fire ;)

please elaborate more, I never heard of a 1mw laser burning anything.
 

HIMNL9

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No, 10mW is just not enough for burn objects (but is still enough for burn your retina, if you look directly into the beam or get a direct reflex form a mirror or shiny object, so, always safety in mind, ok ? :))

For burn, you need at least 100mW, as example blu-ray (405nm) or green, and also you need to focus the beam in a point at some centimeters from the aperture (more precise is the focusing / small the point, more it can burn)

But, ofcourse, 100mW is not a toy ..... remember, you only have 2 eyes, and at the moment, they cannot be repaired nor changed ;) .....
 
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On youtube and on ebay they claim to be able to burn matches!!!!!!!!!!!!!!!!!!!!!!!!!!
 

MikeBP

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post a video, most say they pot mod it into a burning laser, you need at least 100mw to set a match iirc
 
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A properly focused BR laser can light a match at only 30mw. Any amount of power is enough to burn something once the dot becomes small enough, but that becomes very difficult to do at powers <50mw.
 
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Most likely, as you said you saw this on eBay, it is someone who telling a lie to get you to buy the laser.

A) Either it is really 1mW and will not burn anything,

B) or it is NOT 1mW and is very much over powered.
 
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I've seen a high power green laser being sold on ebay claiming to be a 1mw laser. This was due to it being sold in australia where anything over 1mw is illegal. They went out of their way to let any laserist know it's NOT a 1mw laser by listing the pump diode's output. However 1mw it wasn't
 
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You have to think about how much a heat one milliwatt would actually be able to produce even if it were to be focused on a very particular point. Would that point heat up enough to cause a series of chemical reactions allowing the substance to catch fire or combust with only one-one thousandth of a Watt of power?
 
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Power is not what burns. You need an optical density high enough to do "work" on a given substance. The optical density needed depends on a lot of things though. Lasers are used to induce chemical reactions all the time. Consider sunlight in the same way. Less than 5mw per square cm does nothing to a leaf on the pavement. However, compressing the light from one square cm in area down to one tenth of a mm, will do "work" on the leaf. The burning areas may not be large enough to burn with enough oxygen to start a full flame, but however you look at it, its still burning. Burning can look like lots of things.
 
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How does it burn when i have got a 10mw laser that can't burn? Is it the colour or something else?

Well... I guess it's time for you to do a little research on the Forum
to familiarize yourself a bit more with Lasers..
You don't seem to understand the Laser Beam Power required to
produce enough Thermal energy to burn something...

The Forum is FULL of Laser related Info for FREE.... all
you have to do is read it...:cool:


@ Meatball... actually there is about 100mW of thermal energy per
square CM...:beer:


Jerry
 
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Whoa! That's surprising! I read that a 1mw laser can appear brighter than looking into the sun! I suppose my guess was far off.. Thanks for correcting me!

:beer:
 
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think about it. 100mw per cm squared is 1mw per mm squared. Now factor in that a lot of the light from the sun is IR and UV. That 100mw from the sun isn't 100mw of visible light. take a green laser with it's apparent brightness, at 1mw. now assume the beam has a cross section of 1 square mm. it's still going to look brighter then 1 square mm of sunlight would, despite the same power output.

as for beam cross section, do the math at pi times the radius squared = surface area. :D 1 square mm beam is a bit wider then 1mm.
 
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Whoa! That's surprising! I read that a 1mw laser can appear brighter than looking into the sun! I suppose my guess was far off.. Thanks for correcting me!

:beer:

Yeah... on the earth... on a bright sunny day... with the Sun at
90 degrees to the surface of the ground (directly overhead)...
there is 1000Watts of total Solar energy per Square meter..
factoring in the losses through the atmosphere...

That's 1000 Watts / 1,000,000mm = 0.001 Watts/mm or 1mW/mm..:cool:


Jerry
 





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