Instructables

TEA Nitrogen Laser

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Lasers are versatile, incredibly useful, and prevalent in much of the technology we use today. They can carry information over long distances, burn stuff, analyze chemicals, impress people, and do a host of other awesome things. Why not build your own?
I've wanted to build a TEA laser for a while now, and I've finally gotten the parts and the time. Here is the building process along with everything else useful I've found for building your own laser.

First, the necessary disclaimer:

I am not responsible for you, or anything you do. If you hurt yourself I may offer you condolences, but please don't try to sue me for anything.

If you follow the safety advice given and use common sense, you should be fine.

Also, I am obviously not the first person to come up with this idea. The sources I've used the most are:

Nyle Steiner's pages (http://www.sparkbangbuzz.com/tealaser/tealaser7.htm)
The Joss Research Institute (http://www.jossresearch.org/lasers/),
Sam's Laser FAQ (http://www.repairfaq.org/sam/lasercn2.htm),
The Professor's Homebuilt Lasers website (http://www.repairfaq.org/sam/lasercn2.htm), and
Wikipedia (www.wikipedia.org)

Before following this instrucable, it would probably be a good idea to look at some of these excellent resources.
 
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Step 1: Before you start...

Picture of Before you start...
Before you start, there are some questions you might have.

What is a TEA laser?

In short, TEA stands for Transversely Exited Atmospheric pressure laser. While a true nitrogen TEA laser uses a nearly pure nitrogen environment at atmospheric pressure as a lasing medium, the laser I built uses plain old air which has enough nitrogen in it to lase. A TEA laser works by using high-voltage coronal discharge to excite nitrogen in the channel between the electrodes to the point at which it lases. For more details, a good explanation can be found here: http://192.197.62.35/people/mcsele/lasers/Mechanism.htm (The Professor's Homebuilt Lasers Site).

Why build a TEA laser?

Other than the self-satisfaction of having built a laser, there are a handful of ways to motivate yourself. For one, building this laser can acquaint you with skills that are useful in other parts of life. Doing projects like this one forces you to think in a creative way and learn to solve different problems. Even learning to work safely with high voltage electricity can be a stepping stone to other more interesting projects.
This particular type of laser can be built with stuff you have lying around at home, and it doesn't require special tools or skills to build. The only part that was tricky to get was the power supply, which I'll cover in a subsequent step.

These are all the questions that my tired brain could come up with. Feel free to submit your own and I will try my best to answer them.
camforman1 year ago
Rather than feeding an industry (garages / tire filler dudes) that preys upon people that don't understand that 80% N2 is still relatively cheap and attainable. N2 inflation originated out of the aircraft industry where a small tire is filled to very high pressures that makes the ignition point of the tire unacceptably low. Why you would want this in your car tire is beyond me.

To refine your air, you can put a candle in a pile of damp sodium hydroxide (soap making supplies or draino) light the candle and cover it with a vase or bell jar. The candle will consume about 3/4 of the O2 and the lye will react with the resulting CO2. You should be able to get about 95% N2 this way. A glowing ember or burning material heated with an electric filiment take this closer to 100% but you should wait for the lye to do it's work first or you may convert some of the CO2 to CO that can not be absorbed by the lye. The best would be to use an old flash cube (magnesium wool) as a "getter" as it does not generate carbon monoxide (CO) when starved for air.

Also, since 15~20% of the air is removed (well converted to a pile of washing soda) you will need to either accept some air leaking in or come up with some sort of pneumatic trough with silicone oil or water.

Utilizing yeast & a sugar solution will take this further but continue to generate CO2.

Also, pure CO2 is easily purchased or made: paint ball guns, beer kegs, baking soda & acid, yeast & sugar, emergency bike tire inflaters, etc. CO2 also has the nice properity of being 50% heavier than air so it will "hang" around even if you don't have a perfect seal. You are on your own for adapting this for CO2. I am only assuming you can make a TEA with CO2.
ratgod2 years ago
Nice instructable.

The person you mention in "What is a TEA laser?" (or rather the website) is a professor at my college (Niagara College Canada) and I've seen some of the lasers he shows on the webpage, they are pretty cool. He also gives demonstrations with liquid nitrogen on special occasions at the college.
Dreistein2 years ago
can this by any chance burn things?
Kyerohtaron (author)  Dreistein2 years ago
Probably not. It's kind of weak, especially since air is only 70 something percent nitrogen. However, you could probably stick stuff in the spark gap...
maxjus2 years ago
I have a 12kV neon sign transformer. Could I use that, or is that too high of a voltage? I wouldn't have to worry about x-rays, would I?
Kyerohtaron (author)  maxjus2 years ago
I don't think you'd have to worry about x-rays, although 12kV is a bit too high. However, this project needs DC and NSTs output AC. If you half-wave rectify your neon sign transformer with a microwave diode, it should then give you around 6 kV DC and you'll be all set.
If you have a friend that works in a car dealership or garage, you could probably get your hands and some pure nitrogen =)
Kyerohtaron (author)  nitrodude1502 years ago
Hmm, that could be really useful for improving the output of this puny thing. Thanks for the advice! I'm guessing they use it for welding or something?
No, they use it to inflate car tires now, so it'll be easy to get, but if you get it from a car dealership it will be expensive
Kyerohtaron (author)  nitrodude1502 years ago
Cool! I'll see if I can find a garage to go to.
rcantilina2 years ago
This instructable was very well thought out and written in an excellent manor. Congratulations! Can't wait to see what you build next.
Kyerohtaron (author)  rcantilina2 years ago
Thanks! I'm glad you enjoyed it.
tim1272 years ago
what should the value of the resistor be?
Kyerohtaron (author)  tim1272 years ago
It can be anywhere from 1K to 1M, although according to Nyle Steiner 100K seems to work the best if you decide to use a resistor. Thanks for reading my instructable!