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Am I being safe? 500mw @ 520nm with OD 6

fogus

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Joined
May 14, 2022
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New to high powered lasers and I'm a paranoid sort. I want to check my thinking before I do something dumb.

The laser: www. laserpointerstore.com/products/thor-h-series-laser-pointer/?attribute_wavelength-and-power-mw=520nm+Green+-+500
The expander/focuser: www. laserpointerstore.com/products/3x-magnification-optical-expander/
The goggles: www. amazon.com/gp/product/B07DC6CRSM (they were the most expensive I could find with the highest OD rating)

I was reading on www. lasersafetyfacts.com/styled-2/labels3B.html and www. lasersafetyfacts.com/labels4.html and the difference seems to be that they are saying a scattered beam from <500mw can be viewed while a scattered beam from a >500mw beam cannot be viewed directly, whereas for a "reflected" beam, neither can be viewed (obviously). Am I interpreting this correctly and is this a good understanding?

My laser has a IIIb label, but who wants to take a chance when you're right on the edge? Like, medically, 499mw and 501mw aren't going to be different when it comes to an injury.

I don't have the batteries yet, but I did stick in some CR123A batteries and managed to get it to light up at ~6V. It was about as bright as my 5mw weapon laser initially, but then dropped off to where I could only see the dot dimly in the dark (whereas the 5mw weapon light's beam is visible at night). So, I don't think I've really seen what it can do.

I intend to use the beam expander to give off a fairly wide beam.

I can't really see the dot with the OD 6 goggles on, but I'm betting that when the proper batteries arrive, I'll be able to see the dot better. What do you think? Will OD 6 let me see the laser dot from farther away than a few feet with a 500mw green laser? I would like to be able to see the dot in the daytime if possible.

Practically speaking, who here simply always wears goggles when dealing with >5mw lasers? Do you ever (under any circumstances, such as with a beam expander or at a great distance) go, "Ok, I see it is powered up now and there will be no reflections from shiny surfaces over there" and then take your goggles off to see the beam/dot in its full glory? Or is the only safe way to see the beam to point it upwards (no aircraft of course) and view the beam in the air?
 



Joined
Dec 12, 2012
Messages
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The beam expander may make the laser slightly less hazardous in that it will decrease the irradiance and may increase the size beyond the pupil size (7mm dia). Although I do not know for certain that decreasing the irradiance will necessarily make it safer for the eye.

The issue of practical safety is sorta a touchy topic, as most people (not professionals) do not follow the rules 'correctly'. But there are also too many stories of people (even experence ones) getting eye damage, so its always best to err on the side of caution. So we advice beginners to carfully follow all the rules at least until they gain enough experience to bend them. But we still cannot (and will not) suggest others bend the rules.

For the rare times I'm outside I don't use goggles, but I always make sure to have a safe termination location (not the sky, away from people, no reflective objects, fare enough away {>20ft} etc.). These rules are similar to firearm safety rules.
For indoor high power >100mW, its best to always wear safety goggles.

Keep in mind that I've worked with lasers for a while, so have more experience with the dangers.
 

fogus

New member
Joined
May 14, 2022
Messages
3
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Thank you.

Any ideas on how "bird scare" lasers (~200-500mw) (e.g., birdcontrolgroup.com/agrilaser-handheld "Neighbor-friendly" ) can be used safely?
 




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