Is uncollimated laser light dangerous?

[JimBolder]

I'm new to this whole thing (still not done with my first build yet), and I don't plan on losing my eyesight anytime soon.

I take DMM readings with the actual laser diode on, because my test load isn't really all that accurate.

Wearing laser goggles completely blocks out the uncollimated light, so I can't even tell if the diode is on or not.

So is uncollimated laser light dangerous at ~200mW? Not from looking directly into the light, obviously, but from things like accidental reflections, working on a reflective surface, etc.? :thinking: (I would assume that higher powered 900mW+ lasers are dangerous regardless of focus)

 

[udanis]

Un-Focused lasers are being used as dazers or photonic disruptors Laser Energetics
The dazers from the link about are around 300mw. Keep in mind these still have focusing optics on them to keep the beam size reasonable but the 300mw is spread out over a large area.
If it is just the light coming out of the diode without optics it spreads out pretty quickly and the reflections of an uncollimated light aren't too much to worry about. I personally wouldn't look into an uncollimated laser diode from a close distance, but the power does dissipate fairly quickly.

 

[anselm]

I'd say, if the light comes straight out of the diode, with no lens to focus it into a beam/dot,
then you wouldn't have to worry about going blind off a reflection.
Still I wouldn't wanna look into the diode, even if it spreads like a flashlight.

Edit: too slow...

 

[udanis]

I'd say, if the light comes straight out of the diode, with no lens to focus it into a beam/dot,
then you wouldn't have to worry about going blind off a reflection.
Still I wouldn't wanna look into the diode, even if it spreads like a flashlight.

Edit: too slow...

Wow we almost said the exact same thing lol

 

[AUTO XX]

Its the same as a colored flashlight if it isn't collimated isn't it?
I wouldn't look into a 1+Watt LED flashlight, same holds true for a LD.
I have actually used my 445, defocused to follow a blood trail before.
There is a lot of light (~1.6W) and no trouble seeing where you are going. It does give you a headache after a while though, same as the blue LED flashlights.

 

[Cyparagon]

^not quite. You cannot focus a LED beam very tightly, but your lens can focus a laser beam very tightly, even without collimation. The name of the game is power density, and since it spreads so quickly it is almost harmless after a foot.

 

[AUTO XX]

I think you are missing the spirit of the question.
high powered flashlight is hard on the eyes
non focused laser is hard on the eyes
I was talking about a non focused LD
Both could be pretty harmful if you get close enough to them

 

[Cyparagon]

Yes, but 1/3W of red LED light at the same distance/divergence as a 1/3W unfocused red laser will be less of a risk. Laser light is more dangerous than other light sources if all else is equal.

Put a magnifying glass to simulate the lens in your eye at a distance of both - you'll see what I mean.

 

[AUTO XX]

It lights the tablecloth on fire... What about it?
Wonder when these flashlight dots in my vision will fade

 

[goninanbl00d]

It lights the tablecloth on fire... What about it?
Wonder when these flashlight dots in my vision will fade

You don't get it, do you?

His point is- your eye will focus the laser light down to a tighter spot down to the retina than the flashlight will.

Remember, even uncollimated laser light is coherent. It will focus much further than a non-coherent source, regardless of power.

Hence why it's more dangerous.

Nothing to do with tablecloths, flashlight blind spots or excessive sarcasm.