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Laser in mirror burned it's own diode out?

Infarouge

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So I was playing with my great little 300mw red laser off ebay. Of course then I had to point it in a mirror and try to align the beams. The moment I did the diode went down to a faint glow.

Did I kill it?
 

ElectricPlasma

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So I was playing with my great little 300mw red laser off ebay. Of course then I had to point it in a mirror and try to align the beams. The moment I did the diode went down to a faint glow.

Did I kill it?
I've actually heard on the forums of people killing their lasers this way and it seems to be more common that I would've thought. Are your batteries fully charged? If so then you probably have an LED'd laser diode.
 

Infarouge

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Yep battery is good tried 2nd. So it actually lasers again in a mirror amplifying itself into near instant overload being the radiation can't escape.
Good thing I didn't make a black hole.
 

Infarouge

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Joking aside it raises a question I though about. Why can't even weak 5mw lasers be focused into a small enough spot to burn things?
 

diachi

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Joking aside it raises a question I though about. Why can't even weak 5mw lasers be focused into a small enough spot to burn things?
There's a limit to how small a beam at a given wavelength can be focused. It's called the diffraction limit.

It's catastrophic optical damage (COD). It is dead.
This is why you need anti-reflective-coated lenses for high power, and it's always a good idea to point the laser at a slight angle when going through additional lenses, windows, or other optics.
This^^
 

Alaskan

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Why would you shoot the output of a laser beam directly back into the diode using a mirror? I have had diodes fail just from using of of those small little line producing lenses, due to having too much reflect back into the diode, much less a mirror putting most of the power back into the diode.
 

Alaskan

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Maybe not re-focus but will return power back into the diode and if over-driven to begin with, as we like to do for our pointer laser diodes, is bad news to add more heat back into the diode.
 

Radim

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Yea. That would've sucked for all of us. Pun intended
If the black hole was significantly smaller than lets say proton - what is likely when considerling general laser power, it would just fall through the Earth to the core and stayed there as it could not swallow probably anything. Anyway with this size it would just evaporate very quickly due to to Hawking's radiation before anything could fall into it, probably even faster that its fall inside the Earth's core :) The size of black hole of mass (or energy - remember E=mc^2 where c is just constant) of Earth would be of diameter about 18 mm. So, consider energy of the laser...

So, no worries when playing with lasers and mirrors that you will not destroy Earth. :)

Just saying.
 




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