# 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:** 12\ **Page:** 2
**Author:** ![eltro102](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@eltro102](https://boards.straightdope.com/u/eltro102)\ **Post date:** [June 29, 2013, 12:44am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/21 "2013-06-29T00:44:20Z")
> [@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). That’s because of the light fog, a 100mW laser isn’t that dangerous if you don’t shine it at shiny surfaces, the danger from the diffuse spot is minimal however, most cheap 100mW green lasers are going to spit out a lot of infrared light - because to make a green laser you get an infrared laser and double its frequency with a special crystal, in cheap lasers this isn’t very efficent and the IR output is even more dangerous because your eye has no response to it, so you wouldn’t know if you were being lased until pop! blindness! ---
**Author:** ![eltro102](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@eltro102](https://boards.straightdope.com/u/eltro102)\ **Post date:** [June 29, 2013, 12:57am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/22 "2013-06-29T00:57:25Z")
Here is a useful video : [Green Lasers: What Can Certain mW Do? - YouTube](http://www.youtube.com/watch?v=woiTedSKPrk) ---
**Author:** ![Glazer](https://avatars.discourse-cdn.com/v4/letter/g/a88e57/32.png) [@Glazer](https://boards.straightdope.com/u/Glazer)\ **Post date:** [June 29, 2013, 1:43am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/23 "2013-06-29T01:43:33Z")
I love my laser. It’s self leveling and shoots up, down and level. But I’m looking to upgrade to a 5 axis model. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 29, 2013, 6:53pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/24 "2013-06-29T18:53:45Z")
> [@zoid](#): > > From what I’ve seen those green lasers can be seen along the entire length of the beam. Not really. You can only see the beam because you’re close to the beam and looking along the beam, with your line of sight almost parallel to the beam. If you take even a few steps away from the beam, the beam becomes much dimmer. ---
**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 30, 2013, 2:17pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/25 "2013-06-30T14:17:56Z")
What mW power would you need to produce a visible at night? That is all I really want. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [June 30, 2013, 2:27pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/26 "2013-06-30T14:27:04Z")
> [@zoid](#): > > From what I’ve seen those green lasers can be seen along the entire length of the beam. Why do powerful green lasers do this but not others? You can see the beam (or any other type of light for that matter) only to the degree that it is reflecting off something else. In this case it would be dust and moisture in the air. Why doesn’t my red laser pointer do the same thing? ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [July 3, 2013, 7:54am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/27 "2013-07-03T07:54:34Z")
This picture [https://lh5.googleusercontent.com/-ym\_2paAEyTs/UdPVZ-cCe8I/AAAAAAABTbg/Mum0Ayxet90/s0/e26\_83488484.jpg](https://lh5.googleusercontent.com/-ym_2paAEyTs/UdPVZ-cCe8I/AAAAAAABTbg/Mum0Ayxet90/s0/e26_83488484.jpg) is relevant to this thread. At first glance, you can’t figure out what it is. Very poor photoshop? Image artifact? Some kind of HUD/targeting system? Then you see the beams pointing up and realize **it’s a crazy load of laser pointers pointing at a military helicopter**! More pictures here: [Millions March in Egyptian Protests - The Atlantic](http://www.theatlantic.com/infocus/2013/07/millions-march-in-egyptian-protests/100543/#img26) How do Egyptians get so many laser pointers? > [@CookingWithGas](#): > > Why do powerful green lasers do this but not others? You can see the beam (or any other type of light for that matter) only to the degree that it is reflecting off something else. In this case it would be dust and moisture in the air. Why doesn’t my red laser pointer do the same thing? Seeing nobody else answered - red lasers CAN do the same thing. It’s just that normal red lasers are only 1 mW - too weak to see the beam. Wicked Lasers has 100 mW red lasers where you can see the beam. Also, the eye is less sensitive to red light so a higher power is needed than green lasers. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [July 3, 2013, 3:27pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/28 "2013-07-03T15:27:36Z")
If you watch the news from Egypt, the lively crowd in Tahrir square seems to be full of people with green lasers. Every so often one flashes the camera. Someone even had a laser light show device, projecting pictures and words onto the side of a building… ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [July 3, 2013, 10:34pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/29 "2013-07-03T22:34:14Z")
> [@AaronX](#): > > How do Egyptians get so many laser pointers? They’re flooding into Europe (and I guess North Africa too) from China by the container load - here in the UK, they’re quite highly restricted, but still being imported in huge numbers in component form, then assembled and sold through various channels such as market stalls and ebay, etc. And as in many cases of cheap, bulk electronic items from China, they’re not necessarily safe, or properly labelled or documented. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [July 4, 2013, 1:16am UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/30 "2013-07-04T01:16:02Z")
I mean, aren’t they protesting unemployment and poverty? A laser pointer seems an odd choice to make. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [July 4, 2013, 9:15pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/31 "2013-07-04T21:15:47Z")
Many of these protesters are students. The problem is, when they graduate, they will have no prospects for jobs. A lot of people also have cellphones. We’re not talking dirt-floor-and-donkey poor. Google laser pointer and the ads list some (even green) for under $10. Imagine how cheap in a country where the middle man markup is not at US levels… ---
**Author:** ![jasg](https://avatars.discourse-cdn.com/v4/letter/j/f0a364/32.png) [@jasg](https://boards.straightdope.com/u/jasg)\ **Post date:** [July 4, 2013, 11:11pm UTC](https://boards.straightdope.com/t/high-powered-laser-pointers/662077/32 "2013-07-04T23:11:18Z")
Just pay attention to the warning label that says: “WARNING : Do not look into laser with remaining eye.” - and you’ll be fine. [Previous page](https://boards.straightdope.com/t/high-powered-laser-pointers/662077.md?page=1)