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Where to get a bare laser?

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I'm not sure if you are the same person, but a similar discussion went on over here:
**broken link removed**

To put it bluntly, this is a bad idea that will not work.

I'm not sure that you understand the power levels required to light a cigarette. You are talking about a laser bright enough that looking at its dot on a wall can cause permanent eye damage. Even a chance reflection between a few windows or a glass of water will blind you instantly.

This is not going to look cool or be impressive. In the best case (Where your idea works), you are going to see a bright flash of light and then nothing for the rest of your life.


Just to clear up the information, if you really want to go through with this, you will need at least 250mW and probably closer to 500mW. Lighting cigarettes has been done but you will need to hold it exactly at the focal point of a focused laser for ten seconds or so. To make this safe you will need some heavy duty eye protection which will filter out all the light (Aka you won't see the action).

Laser diodes are extremely easy to destroy and are generally run from a current regulating LM317 circuit or similar. All the aixiz modules already have a power supply and just need a few batteries.

In my opinion, a far better method is just to stick a cheap red laser into a lighter with a very dim flame and make it look like the laser is doing the work. There will be enough smoke for the laser to look impressive and you will actually be able to watch it light.
 
Sam's Laser FAQ - Preface, Introduction, What is a Laser?, Safety

As far as safety when im building this circuit, is a pair of polarized sunglasses acceptable for protection against indirect light from the laser?

"Do not depend on sunglasses to protect the eyes. When laser safety goggles are worn, be certain they are designed for the specific laser being used. "

One problem is that polarized sunglasses will only block out components of the light of the correct polarization. Wear your sunglasses and look at an LCD screen (like your cellphone, laptop, TV, computer, digital watch, or calculator). Now rotate the screen or your head. Watch as light gets filtered out more and more as you approach a certain angle and then watch as the light is passed through more and more as you move away from that angle. That's obviously a problem since the amount of light blocked is dependent on the viewing angle.

I think laser goggles use materials that simply absorb that specific wavelength (very very strongly) while letting all others through - getting around the polarization viewing angle problem and allowing very selective frequency blocking. The result is you can actually see and your eyes are still protected despite the viewing angle.

Polarized sunglasses of the same strength would block all light equally making everything almost black. Yet, at the same time polarized light (the laser in particular) could still get through- from very little to almost 100% depending on how out of synch your viewing angle gets the polarization of the glasses out of synch with the polarization of the laser.

Obviously for non-visible lasers obviously the goggles are designed to block the non-visible light while regular sunglasses are not- a key difference.

Go out and buy some of the right laser shades for your laser. For example:
Green LaserShades
Red LaserShades
 
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For a laser show, you will need the proper permits for lasers >5mw. It would be wise to find out what limitation on laser power there is before you invest any cash.
 
As for what i am going to use it for: imagine an immense laser show from a pocket sized device (not including a power supply) as this will not be a display that people or aircraft for that matter will be in a direct line of sight with and it will be pointed to the sky so the diffused lighting effect isnt an issue more to the point it will be used to accentuate a fireworks show so there will be plenty of smoke and fog to show the lights 90% of the lasers should be seen about 150ft in the air as the fireworks will be fused to fire at 250ft.

The next question will probably be "why so powerful you dont need something that powerful" well i have always been one to overdo things and i want a very bright and impressive display.

OK, waitaminnit. You say with one breath that diffused lighting won't be a problem and aircraft won't be affected, yet you plan to aim it into the sky through fog?

I may be jumping to conclusions here (lordy, that's been known to happen) but unless you know for a fact (and have the documentation to prove it) that there are no air lanes anywhere near your planned show site, the aircraft thing could be a problem. And what do you think the fog will do to the beam? It will diffuse it.

As others have already said, polarized glasses will definitely not cut the mustard. You need to get protective glasses specifically designed for the wavelengths you're working at.

I don't think anybody has answered your question about what 'nm' means. It stands for 'nanometers', and gives you the wavelength of the light. The longer the wavelength, the lower the frequency. Blue light has a shorter wavelength than green light, which is shorter than yellow, etc. Red has a longer wavelength, and infrared is longer still (the lowest frequencies you might be able to see are in the near infrared). For reference, reds are in the 700 nm range, blues are in the 400 nm range, and everything else you can see falls somewhere in between. Check Wikipedia and Google for more information.

I don't mean to sound all harsh or "dude that is SO dangerous" but there are plenty of issues to be aware of. Someone posted the link to Sam's Laser FAQ; read it. Three times. You really need to know what you're doing to put on a show with something which has this much potential to blind someone. With a decent laser you can detach someone's retina pretty quickly. Build in lots of failsafes. ;)


Torben
 
Not to worry Torben. If the OP wants to do this right then I am sure he will need to get insurance. There will be no insurance without proper permits. There will be no permits unless lightshow meets certain guidelines, laser safety being one of them.

I suspect it would be hard to justify 90mw as lower powers usually suffice in lightshows.

Of course this all assumes that the op cares about staying within the confines of the law and maintaining public safety.

The reprecussions of doing otherwise could spell disaster and be very expensive if something were to go wrong.
 
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I have thought a lot about this and i have no plans on putting anyone in danger and i am going to test it by myself before there is a large audience but, not to sound harsh, i think some of you are thinking a little too much into this. lasers through smoke is not going to blind someone as easily as you think it is i promise and as far as permits for a light show in the texas desert :D im thinkin ill be ok. And fortunate for me there are no laws against the personal use of high powered lasers or even regulations that would inhibit me in this endeavor. I am also going to take my finished and perfected project to my school for a little show, which will also be tested before performed of course. Thanks for the link to sams laser guide it look useful but to torben i think its funny you tell me how what i am doing is dangerous but you tell me to read sams laser guide 3 times and it has a how-to for building a 10W laser at home ;)
Mike bits i hate to let you down my im not an insurance kind of person for public displays so ill just have them all agree to do a mass verbal taped agreement to watch the show and their own risk or maybe a sign in sheet for it. either way i think ill be ok and keep in mind although i did not state this earlier there will only be like 10-20 people in a big ....... well desert

Now i have a 200mW, 12mW both red and a i think 15mW green laser all ready to go i just need to adjust the lenses to the focal point i want and start to figure out the way to make a circuit of mirrors and motors. Which is my next project. I know of a little soldering kit to make light show so i am going to maybe get the schematics from that so start making my own curcuit, :D and of course any other constructive ideas are always welcome.

Thanks everyone for all your help and wonderful links.:)
 
I'm not so worried about people on the ground because the lasers are probably shining up, but planes fly everywhere and a desert or city is all the same when you're in the air. A pilot does not need to go blind for things to get dangerous.

**broken link removed**

**broken link removed**
 
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Trust me i will be no where near a flight path or airport and the focal points of the lasers will be set so that if there was for some strange reason a plane over head all they would see at their altitude is a strange light from the ground but if the US Govmt shows up with black hawks and special forces ill know someone saw me and thought i was a UFO lol
 
As far as safety when im building this circuit, is a pair of polarized sunglasses acceptable for protection against indirect light from the laser?

No, not even close. There are two issues with laser safety goggles. You need to completely block the wavelength of the laser radiation, and you need them to completely wrap around the eyes so refections can't hit your eyes from the side. Standard sunglasses (of any type) don't do either of these things. One exception is those blue-blocking amber sunglasses that block, blue and green light, but they don't completly cover the eyes.

You need to buy specially designed laser safety goggles matched to the wavelength you are dealing with. If you end up going with a green laser, then the goggles used for Argon-ion lasers should be suitable. You will not be able to see the beam at all with the proper safety glasses. This can introduce another safety hazzard, since you may burn your skin inadvertantly since you can't see the direct, or reflected light.

You are talking about high power lasers, so even the 4 % reflection off of glass will blind you, and a stray reflection off of metal is much worse.
 
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Thankfully i live in a state that we dont detain people for such inconsequential events even if there was some way that a airplane was in anyway in a line of sight with my mighty lasers but as i have said again and again and again................again ....... there will not be any aircraft involved at all. So you will all be relieved to know that the endangered airplane pilot is safe and will always be able to land safely AND there is a lake nearby the location so hope fully Chesley B. "Sully" Sullenberger will be flying the airplane that way everyone will be ok. i hoped to do this with a very small bit of Ω but i knew there would be.
 
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