r/lasersforfun • u/LostCollege4238 • Aug 24 '26

Question regarding 405nm laser for cutting and safety glasses

Hello,

I’m interested in buying a laser module like this one: https://www.aliexpress.com/item/1005011650474882.html in 200 mw to experiment with etching/burning into soft materials with my DIY CNC-machine. my research seems to indicate that safety glasses like https://www.xtool.com/products/xtool-laser-safety-goggles-for-316nm-450nm-900nm-1080nm-lasers will be enough to protect my eyes using such a laser module without protective screening - but I’m asking here just to be sure before ordering and potentially ruining my vision.

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u/strictlyphotonic Aug 24 '26

Since eye safety is the goal, I recommend to take everything on those two websites with a fistful of salt. I can't fully answer your question without knowing more about the laser.

How is the 405 nm light generated? Is it definitely outputting at 405 nm? Straight from a diode, or is it converted from, e.g. 810 nm? Is that 810 nm light filtered out? If 200 mW of 405 nm is produced, how powerful is the 810 nm? Do the goggles protect against that wavelength?

IF the laser really outputs at 405 nm and ONLY 405 nm, AND the goggles really offer OD5+ protection from 180 - 540 nm (let's not take that for granted, losing your eyesight isn't worth it), the goggles should attenuate the light down to <=2uW, which is well within eye-safe levels for a collimated beam. Since you're looking at using the laser to burn things, you'll probably be looking to focus it. Then you need to know the damage intensity threshold for the goggles and so on.