How safe is my laser?

Hi everyone!

I just received my first laser which I purchased from DX a few weeks ago.

Since I placed my order, I have read about the dangers of looking at the projected dot from high powered lasers.

The laser I have received is supposedly a "<5mW 532nm" model powered by an 18650 battery

Having read about the risks of invisible IR radiation, I have been very cautious so far. What I have discovered is that the beam is just visible in a fairly well lit (lit by artificial light) room. I also placed a black bin liner over the front of the laser and found that this burnt a small hole through the bag almost instantly.

I was just after some opinion on the likely actual output of the laser? (surely more than 5mW if it burns through plastic?), and also how much of that power is likely to be invisible radiation? (maybe quite a lot given that the visible beam isn't that bright in a well lit room?)

I would like to have some idea so I know how careful I need to be when pointing the laser at things I am looking at, or at objects visible to other people - I don't want to harm anyones eyes!

Thanks

the laser is probably doing at or a bit over 50mW maybe up to 100mW but I doubt it. never shine it in anyones eyes, it is strong enough to cause damage. the IR is not as much a danger with green lasers as pure IR lasers, at least the green shows where the IR is also going, and your pupils still react to the green, pure IR is totally invisible, much more dangerous. the dot of your laser should be ok to look at at distances greater than a foot, If I recall, irradiance decreases with the square of the distance from the dot, so unless you shine it at a mirror or similar reflective surface you should be ok. lasers approaching the 500mW mark is when you have to start worrying about this more

basically treat it like a gun, point it only where safe and only power it on if you know it's safe. there are glasses that protect from both IR and green light, they're pricey. mostly safety glasses are to use while burning, to safely view dots of high powered lasers, or any time you might catch a beam to the eye. other than those situations, i cant think of many needs for glasses with your particular laser, just be very safe. lasers are no joke, they deserve much more respect than most give them

good on you for coming here to learn more BEFORE a catastophy.

cant tell you how much IR you laser is outputting. the only way to tell is with an IR filter and LPM

no way in heck would a true 5mW 532nm beam be visible in a lit room with no fog, sadly low powered 532nm lasers are plauged by this overspec problem, I see it all the time, people think they have an eye safe (blink reflex) laser and then go out and do dumb things that should not even be done with an "eye safe" laser

be careful all lasers sold there lack ir filter.

Ok, so the reflected light from (for example) a white wall 6' or 2 metres or more away should be OK?

Not pointing it directly at, or even near to, another person goes without saying!

Thanks for the replies

gravelrash said:

Ok, so the reflected light from (for example) a white wall 6' or 2 metres or more away should be OK?

Not pointing it directly at, or even near to, another person goes without saying!

Thanks for the replies

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Yes you will be fine looking at the reflection if you are 2/more meters away

my hene is moderately visible in a lit room.... you can't really judge it by brightness alone. but I do think you're in little danger as long as you don't get it in your eyes. (or anyone elses) which you should always aspire to anyway.

Can you post a photo of the beam ? curious to see how strong it looks.

mortuus said:

Can you post a photo of the beam ? curious to see how strong it looks.

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You can't judge a lasers power by it's beam

mortuus said:

Can you post a photo of the beam ? curious to see how strong it looks.

Click to expand...

Not easy to get a photo of!

Taken on a dull January day with the curtains open...

Bright enough, no where near 5mw, got to be more like 50mw, especially if it can burn black plastic.

Alan

Ha! I needn't have worried. With probably only just over a minute of "on" time in total, in short bursts of a few seconds at a time, the laser has suddenly decreased in brightness by a factor of at least 10. The beam is no longer visible in even a darkish room, and the dot is small and comfortable to look at. I am guessing something burnt out.

Oh well. It was kinda cool having a laser that burnt holes for a short while. I hope it is still bright enough to server its intended purpose as a star pointer.

Maybe I will look at the buying guides on this website and get myself another one that is intended to burn stuff

Cheers

Steve

Actually, I just thought that a review of these might be useful to other people....

The full story is that I made my original purchase back in October. The first laser I received burnt out in less than 5 seconds of use. It started fairly bright when I first powered it up, then quickly dimmed, and then would only produce a faint green flash on powering up.

I raised a return with DX, and I finally got the replacement this week. Sp a good 3 months in total turnaround.

As discussed in this thread, the replacement started out overspec (I was quite pleased about that!), but has now faded to either near claimed 5mW or below.

The item is this one from DX: SD-301 5mW 532nm Green Laser Flashlight - Black (1 x 18650) - Free Shipping - DealExtreme

I will update if it degrades further in use or if I decide to attempt another exchange

Thanks Im glad to know to avoid this company for sure Because I was just consdering my first pirhcase of a high power green laser..

I wouldn't say my comments should put you off DX altogether.

I have a history of using DX for LED flashlights and bike lights.

I found with those that you could find out on forums which are good and bad models to buy.

They do at least have a sound returns and exchange policy. The three month turnaround is quite slow, but is partly down to when I placed my original order. China goes on holiday sometime in October, and orders placed at that time can get seriously delayed.

I do suspect that this particular model of laser from DX has some manufacturing quality issues. The same might not apply to another model. I don't know enough about lasers to distinguish the good from the bad.

I've had the same problem wi th my 100mw 523nm as advertised laser. It now functions below 5mw if that sometimes I can shake it to get more power but I had th same problem with my Chinese green laser

xirrious said:

I've had the same problem wi th my 100mw 523nm as advertised laser. It now functions below 5mw if that sometimes I can shake it to get more power but I had th same problem with my Chinese green laser

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I'm very new to all this, but I think my problems might have been due to alignment issues with the optical path of the laser.

I decided to pull mine apart to have a look, and was a bit surprised to find the various bits of the optical path to be rather vaguely glued in place with flexible silicon-sealant type glue. I think my laser stopped outputting the really bright burning power beam after having a bit of a knock, and I suspect it may have caused one of those bits (crystal or collimating lens) to move a tiny bit.

I can now get mine to output something like a fairly well focussed faint green torch by positioning the bits back together as best I can, but I have little hope of ever making it work as a true laser again. It is very sensitive to incredibly small changes in position of the crystal and collimating lens.

If I can work out how to get the laser module itself out of the SD 301 host then I will probably try buying a cheap module from fasttech or someone similar