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Should you have an infrared filter to be safe?

jj236

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I'm using a laser pointer for astronomy and pointing at the stars.
Therefore the laser beam isn't in the direction of someone's eyes.
But it doesn't stop people from looking at the laser pointer.

If I'm pointing the output of the laser into the sky, is infrared still a safety concern?
Is infrared energy leaking out around the beam or the pointer?
Does infrared energy emit an approximate 360 degree pattern, therefore potentially harm people though the beam isn't directed towards their eyes?

Thanks in advance.
 

Mosc007

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The IR beam is combined with the 532 beam. It's main safety concern is that you cant see it.
 

jj236

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If I look at the laser beam (that's purpose of a laser pointer), will I be receiving infrared? Or does the laser beam need to be pointed near the eyes?
 

WizardG

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If I look at the laser beam (that's purpose of a laser pointer), will I be receiving infrared? Or does the laser beam need to be pointed near the eyes?
Since the IR is going in the same direction as the green light, yes there will be some tiny amount of IR that scatters in the air, just as a bit of the green light is scattered. If your eyes could see IR light but not green light you'd still be able to see a beam. The IR that is scattered is not intense enough to be a hazard unless the laser is pointed at someone's eyes just as the scattered green light that you can see as a beam in the air isn't hazardous unless you point the laser at someone's eyes.

If that isn't clear then just understand this: DO NOT point ANY laser at anyone's eyes (or at aircraft or buildings or cars, boats, etc) and you'll be fine.
 

jj236

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This manufacturer makes some confusing IR filter suggestions:

Product Item #1:
IR filter removes 95% infrared light @ 532nm
Output Power ~5.0 mW


Product Item #2:
IR filter not required on semiconductor XT diodes
Diode Circuit Type - OSRAM Semiconductor 515nm
Output Power ~5.0 mW


An IR filter for 532nm, but not 515nm?
or
An IR filter not necessary for OSRAM, but suggested for non-OSRAM?
 

paul1598419

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I assure you the amount of IR in a solid state laser like the green 532nm one is very small when compared to the amount of visible light. You will never have IR in a direct diode laser unless it is an IR laser. As long as you don't hit anyone in the eyes with your laser you have nothing to worry about. I have looked at the IR component with a spectrometer in 532nm lasers and it is very small compared to the visible component of these lasers. A 5 mW one would have so little IR that I doubt it could cause one harm even if you hit someone in the eye with it. Your blink reflex is 0.25 seconds and that is enough time to get away from a 5 mW laser before it can damage the retina. This doesn't mean you should try staring into it as that would cause you harm.
 

Immo1282

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Paul's right - the danger is exaggerated with a low-powered laser to start with - don't look at the beam and you'll be fine.

IR filters are not needed on direct diode (for green lasers, this is anything other than 532nm) lasers as they are monochromatic on their own wavelength (i.e. only emit 515nm light, no IR). 532nm Lasers are Solid State lasers pumped by an IR diode - i.e. they use an IR diode, and modify it's wavelength through two crystals. The IR from a 532nm pointer is there because it leaks through those crystals without being converted into green light.
 

diachi

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The IR beam is combined with the 532 beam. It's main safety concern is that you cant see it.
Well, that and the fact that if you have glasses for 532nm they'll be no good for the IR portion, which will pass right through.
 




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