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ArcticMyst Security by Avery

Why do green lasers dim?

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Mar 8, 2011
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Why does my green ebay laser dim after turning it on?

when it warm it stops doing it?
 





daguin

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Getting green from IR requires precise alignment, angles, and polishes. As the laser and crystals heat up, the components expand. This expansion alters the alignments and angles. As the angles change the efficiency of the conversion changes.

Peace,
dave
 
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Ohh , my camera did detect some IR, but I ave two IR cut filters from a few old cameras, so I'll put that in.

It still dims even when it's warm, but later when I turned it on.
 

daguin

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Ohh , my camera did detect some IR, but I ave two IR cut filters from a few old cameras, so I'll put that in.

It still dims even when it's warm, but later when I turned it on.

There is an IR pump diode shining through a set of crystals that double the frequency to get the green wavelength. The IR isn't making the laser brighter and dimmer. The IR output from the diode is not changing. It is the alignment changing that is doing it. When the alignment changes, the efficiency of the doubling process changes. The output will get higher and lower. The mode will change.

Your particular laser goes through some changes as it warms up and "finishes" with good alignment and a good output. Be happy and grateful. It could be the other way around. It could start out wioth a good output and then go downhill as it warmed up. This second condition is what MOST problematic DPSS lasers do.

As long as the components are moving about (as the metal parts and the crystal heat up) the output will continue to vary. That is why most good lab-style lasers have a TEC in them to control the temperature.

Your laser will go through the same changes every time you turn it on (with some minor variation) until something overheats so badly that the alignment will not return to the original position or the crystal burns

Peace,
dave
 

anselm

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Also, as the IR diode heats up, it might shift a few nm in it's output wavelength.
The crystal has a very narrow band for optimal absorption, the IR light
from the hot diode might be outside that optimal window.
 
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OK, thanks you both for the good informative replys.


I should even think of potmodding?
 

daguin

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OK, thanks you both for the good informative replys.


I should even think of potmodding?

All you will do is burn out your diode or crystal faster

If you want a more powerful laser, buy one or build one

Peace,
dave
 
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All you will do is burn out your diode or crystal faster

If you want a more powerful laser, buy one or build one

Peace,
dave


OK thanks.

But some on youtube actually work, do they just burn out later?
 
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Is it possible to see a 1mW beam in daylight?

Also it says on the laser <5mW

Because I can see it.
 
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Then it's nowhere near 1mW. A visible beam in high ambient light conditions requires significant power. Certainly over 50mW.
 
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Well I'm not joking my unmodded 1mW produces a clearly visible beam at day, and at night it is brilliant. But the laser is in parts now, I took the IR diode out, and that how I damaged my eye.
 
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Then it is unlikely it will ever work again. Especially if you were burning stuff at close range with an uncollimated diode. I'm sure you funked up the diode window something awful.. Which is pretty much impossible to clean.
 




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