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How can one tell if a laser has an IR filter, except by the specs?

inspiration100

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Probably a stupid question but I've never read a direct answer to this... is there any way I can tell that a laser pointer has an IR filter other than trying to dig up the specs? Can anyone tell me exactly how I can figure this out?

Thank you :)
 

chipdouglas

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you can test it with a cheap digital camera like on a cell phone. or in some cases if you take the aperature cap off it is an added piece after the lens assembly. now mind you, you will only have ir in ir lasers (which obviously you don't want to filter), and in dpss systems. diode lasers do not emit ir.

michael
 

HIMNL9

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And for do a quick check with a camera, you can use an IR-pass filter.

You can find them in pro shops, fro insanely high prices (optic quality), but considering that you only need to check for IR presence, you can get one very cheap (usually for free) if you know a photo lab in your zone.

Just ask them for the "black queue" of a developed "diapositive" film ..... is the part that remain in the roll and unexposed when they send it to develope, and that is totally black when the film come back (usually any serious lab, sending back the dias in the frames, always include also the unexposed and developed "queue" for testify that they have developed all the roll)

This black film is an almost totally block filter for visible light, but is 95/98% transparent to the IR ..... point the laser on a piece of white paper, put it in front of the laser, and look the paper with the camera ..... the more "pinky" light you can see coming from the film, the more IR are leaking out from the pointer (only be careful with high power lasers, that filter is still plastic, and can be burned from high power beams :p)
 

Antimony Trioxide

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Pretty much a rule of thumb, if it looks like this








then its not filtered
 
Last edited:

Mik

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Look at the lens of the laser. IR filters that I've seen are typically blue tinted glass, pretty easy to spot.

The other thing I like to do, is shine the laser through my sacraficed pair of green laser safety glasses into my LPM. Anything that gets through I can assume is IR. The glasses block 532 really well but pass all IR.
 




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