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Have I been exposed to dangerous levels if IR from my 5mW green laser?

nzoomed

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About 10 years ago, i bought a cheap 5mW laser from china (my first such laser).
Only some time later I was reading about these cheap lasers that had no IR filters installed (this was made by new wish laser in china).
Even though they put out 5mW of visible green light, some potentially produce hundreds of mW of IR light and not in a focused beam but more of a wide conical beam like a flashlight does.

Is any of this true?
I believe its only a real danger with the ones that claim to pop balloons, etc.
This laser certainly was unable to do so, but from what I understand, a green laser diode produces IR, but generates green light by means of a similar process to fluorescence and converts some of that IR energy into visible green light.

I was always careful not to shine on reflective objects, but since the laser could have potentially produced scattered IR, it may have reflected off other objects without me knowing.
I later replaced the laser with one that had a built in IR filter. I did not use the thing a huge amount, but still was a bit concerned.
 



Hap

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I don’t think that laser was outputting anywhere near 5mW’s of 532 light. Lasers that do tend to be quite more expensive then those cheap lasers :)

-Alex
 
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GSS

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Yup, like Hap said.. That laser of yours is most likely puts out anywhere from 50mw to 90mw.
10mw to 25mw only might be IR. The IR is focused tight enough and away that you need to worry of being exposed.
 
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paul1598419

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If the IR were conical it would pose no danger at all being basically an IR flashlight. The IR "leaking" out is 1064nm and is quite low in power, but is still collimated along with the visible beam.
 
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Snecho

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Yes, quite a bit of misunderstanding in the OP. That laser most likely had a total output of 5-100mW. 532nm is DPSS, which means it's an IR diode going through some crystals to make 532 light. As a result, without an IR filter, a small portion of the IR leaks out.

This IR light makes up no more than about 20%, usually less, of the total output power. And, as Paul said, it follows the exact same path as the main beam so if you didn't get hit with the green beam, you didn't get hit with IR.

Also, you mentioned green laser diodes (AKA, Direct Diode Lasers). There are no 532nm green diodes. There are 505-520nm and 525nm diodes that are green, but regardless, diodes themselves output the stated wavelength instantly. Therefore, there is never any IR light to be had, unless the diode itself is an IR diode. :)


As a side note, the true power of unfiltered 532 light is less than what's measured on an LPM. For example say you have two 532nm lasers that both measure 100mW on an LPM. One has an IR filter and the other doesn't. That means the one with the IR filter is visibly brighter than the other because it's power is 100% green light (100mW of pure green light), whereas the unfiltered one is 80% green and 20% invisible IR (80mW of green, 20mW of IR).

Hope that makes sense. DPSS lasers are tricky 🙂
 

nzoomed

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OK interesting read.
I had read many threads about the make of laser (from NewWish laser) such as this one here
It looked identical to this and ran off a couple of AAA


batteries.
I threw the thing out about 2 months ago because I dropped it and the diode went out of align inside and no longer produced a nice beam and the dot was almost a foot across after about 20M lol


Yes, quite a bit of misunderstanding in the OP. That laser most likely had a total output of 5-100mW. 532nm is DPSS, which means it's an IR diode going through some crystals to make 532 light. As a result, without an IR filter, a small portion of the IR leaks out.

This IR light makes up no more than about 20%, usually less, of the total output power. And, as Paul said, it follows the exact same path as the main beam so if you didn't get hit with the green beam, you didn't get hit with IR.

Also, you mentioned green laser diodes (AKA, Direct Diode Lasers). There are no 532nm green diodes. There are 505-520nm and 525nm diodes that are green, but regardless, diodes themselves output the stated wavelength instantly. Therefore, there is never any IR light to be had, unless the diode itself is an IR diode. :)


As a side note, the true power of unfiltered 532 light is less than what's measured on an LPM. For example say you have two 532nm lasers that both measure 100mW on an LPM. One has an IR filter and the other doesn't. That means the one with the IR filter is visibly brighter than the other because it's power is 100% green light (100mW of pure green light), whereas the unfiltered one is 80% green and 20% invisible IR (80mW of green, 20mW of IR).

Hope that makes sense. DPSS lasers are tricky 🙂
Thats helpful
 

nzoomed

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GSS

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I also forgot to show the type of housing i bought for the diode, I dont think its anything ultra high spec.
I'm bit confused..
What diode and host are you planning for this module you posted?
 

nzoomed

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I'm bit confused..
What diode and host are you planning for this module you posted?
Im using a Nichica M140 diode and lifetime17 has supplied me a host that I will use the housing in from the above Ebay link.
 
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GSS

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Im using a Nichica M140 diode and lifetime17 has supplied me a host that I will use the housing in from the above Ebay link.
Nice match!:)
I must have 10 hosts and builds from Lifetime17...Enjoy and be safe..
 




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