# High Powered Laser Pointers **URL:** \ **Category:** Factual Questions\ **Created:** [June 28, 2013, 12:11am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077 "2013-06-28T00:11:47Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![The\_Man\_In\_Black](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@The\_Man\_In\_Black](https://boards.straightdope.com/u/The_Man_In_Black)\ **Post date:** [June 28, 2013, 12:11am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/1 "2013-06-28T00:11:47Z")
I was with some friends last night, and one girl pulled out a green laser pointer. The beam was very visible, like a lightsaber that went on forever. Today I was thinking that I’d like to get one, so I was looking at them online. My main question on the safety of using high powered lasers. When using lasers 100mW and up, is just looking at the dot it creates on a wall dangerous? I know not to stair into the damned thing. But I seem to be reading that you need special goggles just to loom at the dot it creates. Is that true? ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [June 28, 2013, 12:36am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/2 "2013-06-28T00:36:30Z")
You can ( **and I do not recommend this** ) blind the pilot of a low-flying aircraft. Which is _ **highly illegal!!!** _ As in “lock you up so deep in the ground that they will have to pipe sunlight down to you” locked up. ---
**Author:** ![Emtar\_KronJonDerSohn](https://avatars.discourse-cdn.com/v4/letter/e/58956e/32.png) [@Emtar\_KronJonDerSohn](https://boards.straightdope.com/u/Emtar_KronJonDerSohn)\ **Post date:** [June 28, 2013, 12:37am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/3 "2013-06-28T00:37:19Z")
The green light itself is not such a big deal, but cheap green lasers generally put out a metric shitload of light on the invisible part of the spectrum that will damage your eyes. That light is not always tightly collimated in a neat little dot like the green light, it shines over a much larger area and reflects and can damage your eyes. I have a handful of such lasers and my experience is that they were fun to play with a few times over the course of a few weeks and by the time they lost their novelty and became dust collectors on a shelf in the garage I had likely not been exposed to enough light to cause irreparable damage. YMMV, IANAPhD, etc ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [June 28, 2013, 12:44am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/4 "2013-06-28T00:44:42Z")
yes reflected laser light can cause damage if it is intense enough, depends on lots of factors. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 28, 2013, 1:53am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/5 "2013-06-28T01:53:39Z")
100mW is WAY eye-unsafe! This is total overkill. I have a 5mW green laser, and it’s plenty bright. The only way you should be using a 100mW laser is with the correct wavelength filter goggles. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [June 28, 2013, 1:55am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/6 "2013-06-28T01:55:27Z")
Stare. ---
**Author:** ![Sasquatch\_1](https://avatars.discourse-cdn.com/v4/letter/s/8491ac/32.png) [@Sasquatch\_1](https://boards.straightdope.com/u/Sasquatch_1)\ **Post date:** [June 28, 2013, 2:50am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/7 "2013-06-28T02:50:33Z")
A 100 mW green laser spot on a matte surface should not be dangerous to look at, although in my experience, that’s about the level it becomes too bright to comfortably look at on a white surface. That’s plenty to be dangerous either direct or in reflection from a shiny surface though. I think around 500mW to a full Watt output is getting to be dangerous to look at even a diffuse spot. Many green lasers do use IR lasers internally, but only a really really cheap one or a broken one will not have an IR filter. The IR laser inside a green laser can be dangerous, as it will be a lot more powerful than the green laser output, and won’t engage a person’s blink reflex. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 28, 2013, 3:19am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/8 "2013-06-28T03:19:56Z")
> [@The\_Man\_In\_Black](#): > > When using lasers 100mW and up, is just looking at the dot it creates on a wall dangerous? This is actually the dividing line between Class-3 and Class-4 laser; a Class-4 laser can damage your eye if you just look at the dot it creates on a diffuse surface (like a white wall). You can’t buy those without a license in most places. ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [June 28, 2013, 4:01am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/9 "2013-06-28T04:01:52Z")
playing with it indoors is a recipe for disaster if it reflects of a polished surface. ---
**Author:** ![JBDivmstr](https://avatars.discourse-cdn.com/v4/letter/j/b4bc9f/32.png) [@JBDivmstr](https://boards.straightdope.com/u/JBDivmstr)\ **Post date:** [June 28, 2013, 9:08am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/10 "2013-06-28T09:08:38Z")
> [@Emtar\_KronJonDerSohn](#): > > The green light itself is not such a big deal, but cheap green lasers generally put out a metric shitload of light on the invisible part of the spectrum that will damage your eyes. _ **That light is not always tightly collimated in a neat little dot like the green light, it shines over a much larger area** _ and reflects and can damage your eyes. > > I have a handful of such lasers and my experience is that they were fun to play with a few times over the course of a few weeks and by the time they lost their novelty and became dust collectors on a shelf in the garage I had likely not been exposed to enough light to cause irreparable damage. YMMV, IANAPhD, etc (bolding mine) And for that matter, the ‘little green dot’ spreads out quite a bit, with distance. Try shining one at an overhead ‘freeway’ sign at night. At a distance of 1/10 of a mile one of those little green laser pointers will light up a pretty good sized sign (6’ x 10’), significantly. It almost looks like you’re shining a green colored ‘Q-Beam’ spotlight at it. :eek: Partly because the sign has a highly reflective surface, but also because the beam from the laser has ‘spread out’. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [June 28, 2013, 11:41am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/11 "2013-06-28T11:41:40Z")
> [@Magiver](#): > > playing with it indoors is a recipe for disaster if it reflects of a polished surface. And if you play around with a laser long/often enough, it’s virtually certain that this will eventually happen. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [June 28, 2013, 2:37pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/12 "2013-06-28T14:37:46Z")
[http://www.thinkgeek.com/product/5a47/](http://www.thinkgeek.com/product/5a47/) -this is 5mW. They claim it is VERY bright. [http://www.laserglow.com/specsheets/GAR075XXX.php](http://www.laserglow.com/specsheets/GAR075XXX.php) - this one goes up to 11. It has a heat sink. Does not mention power supply? But it looks to be a full-sized flashlight size, and the photo shows a power-brick? plug connecting to it, it looks like C-sized batteries (plus a keyed switch lock for safety). Are you sure 100mW is not someone exaggerating? That is one helluva big laser, I would be surprised if it was a penlight running on a few AA’s. As \*\*sc4 \*\*(and others) mention, it is a significantly powerful number bordering on restricted. Remember, there are two numbers - power consumed, and actual power output. lasers are somewhat inefficient. ---
**Author:** ![Iggins](https://avatars.discourse-cdn.com/v4/letter/i/b9e5f3/32.png) [@Iggins](https://boards.straightdope.com/u/Iggins)\ **Post date:** [June 28, 2013, 3:19pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/13 "2013-06-28T15:19:00Z")
> [@md2000](#): > > [http://www.thinkgeek.com/product/5a47/](http://www.thinkgeek.com/product/5a47/) -this is 5mW. They claim it is VERY bright. > [http://www.laserglow.com/specsheets/GAR075XXX.php](http://www.laserglow.com/specsheets/GAR075XXX.php) - this one goes up to 11. It has a heat sink. Does not mention power supply? But it looks to be a full-sized flashlight size, and the photo shows a power-brick? plug connecting to it, it looks like C-sized batteries (plus a keyed switch lock for safety). > > Are you sure 100mW is not someone exaggerating? That is one helluva big laser, I would be surprised if it was a penlight running on a few AA’s. As \*\*sc4 \*\*(and others) mention, it is a significantly powerful number bordering on restricted. > > Remember, there are two numbers - power consumed, and actual power output. lasers are somewhat inefficient. I have a large pen style Class III green laser pointer that reads, “OUTPUT POWER \<100mW”. It comes with a “diffuser” that breaks the light down to a pattern, instead of a focused beam. Removing the diffuser produces a very bright point. Powered from two AAA batteries. So, it’s not 100mW, but still extremely dangerous… It was purchased in China, probably not available in the US. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [June 28, 2013, 3:36pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/14 "2013-06-28T15:36:52Z")
> [@md2000](#): > > [http://www.thinkgeek.com/product/5a47/](http://www.thinkgeek.com/product/5a47/) -this is 5mW. They claim it is VERY bright. Shine a 5 milliwatt pointer in your eye sometime. It MIGHT not do any damage as long as you don’t stare into it. But when you do it you will think it has. I can’t imagine dicking around with a 100mw one. Yeah, there are times you need that kinda power but get THAT in your eye and its the eyeball equivalent of getting maced and tazed at the same time. Except the damage could easily be permanent. Read a few safety reports of laser accidents and you’ll become much more careful. The ones where people hear their eyes “pop” are particularly interesting. And as someone else noted. Its the wavelengths you can’t see that can do serious damage that you won’t note until the damage is already done. And as we all know that all that stuff from China meets the most stringent safety and quality control requirements… ---
**Author:** ![zoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zoid/32/336_2.png) [@zoid](https://boards.straightdope.com/u/zoid)\ **Post date:** [June 28, 2013, 4:21pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/15 "2013-06-28T16:21:19Z")
Can I hijack for just a second? From what I’ve seen those green lasers can be seen along the entire length of the beam. Wouldn’t this be the perfect safety tool to give backpackers, hikers, and skiers and tell them “Look, if you get lost just shine this sucker upwards in a circle like one of those spotlight thingies they have at car dealerships and we’ll be able to find you”. ---
**Author:** ![bleach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bleach/32/3106_2.png) [@bleach](https://boards.straightdope.com/u/bleach)\ **Post date:** [June 28, 2013, 5:22pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/16 "2013-06-28T17:22:34Z")
That’s a good thought **zoid**. I guess one of the limiting factors is battery life. It may be harder to see a beam during a sunny day, but it could work at night. Not sure if you can see [this picture](https://www.facebook.com/photo.php?fbid=314424478624440&set=o.210511944114&type=1&theater) since it’s from facebook, but here’s an example of a guy using a green 100mW laser to do what you’re describing. The picture shows a guy projecting a green laser beam across a valley (distance of about 3 miles). ---
**Author:** ![zoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zoid/32/336_2.png) [@zoid](https://boards.straightdope.com/u/zoid)\ **Post date:** [June 28, 2013, 6:37pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/17 "2013-06-28T18:37:44Z")
> [@bleach](#): > > That’s a good thought **zoid**. I guess one of the limiting factors is battery life. It may be harder to see a beam during a sunny day, but it could work at night. > > Not sure if you can see [this picture](https://www.facebook.com/photo.php?fbid=314424478624440&set=o.210511944114&type=1&theater) since it’s from facebook, but here’s an example of a guy using a green 100mW laser to do what you’re describing. The picture shows a guy projecting a green laser beam across a valley (distance of about 3 miles). Well shit - I’m going out and buying one of those damn things right now for me and each of my kids. ---
**Author:** ![moriah](https://avatars.discourse-cdn.com/v4/letter/m/b2d939/32.png) [@moriah](https://boards.straightdope.com/u/moriah)\ **Post date:** [June 28, 2013, 6:59pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/18 "2013-06-28T18:59:59Z")
> [@zoid](#): > > Well shit - I’m going out and buying one of those damn things right now for me and each of my kids. Because your family has too good eye sight as it is? ---
**Author:** ![zoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zoid/32/336_2.png) [@zoid](https://boards.straightdope.com/u/zoid)\ **Post date:** [June 28, 2013, 7:32pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/19 "2013-06-28T19:32:02Z")
I mean one of those ThinkGeek ones, not like a real powerful one, and my kids are old enough to know not to look into the thing. ---
**Author:** ![sylmar](https://avatars.discourse-cdn.com/v4/letter/s/b782af/32.png) [@sylmar](https://boards.straightdope.com/u/sylmar)\ **Post date:** [June 28, 2013, 8:57pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/20 "2013-06-28T20:57:48Z")
> [@The\_Man\_In\_Black](#): > > The beam was very visible, like a lightsaber that went on forever. It’s time to find Darth Maul, padwan… [Next page](https://boards.straightdope.com/t/high-powered-laser-pointers/662077.md?page=2)