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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.

Step 1: 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.

Step 2: Safety!

Safety tips:

-- Despite its simplicity, this laser could potentially be dangerous. Even though it probably won't be capable of starting a fire (unless something gets in the way of the spark gap), the peak power can be significantly more than that of a red laser pointer. The output wavelength is around 337 nm (ultraviolet) which means that you should take precautions to avoid overexposing yourself to UV radiation. As with all lasers, letting the beam get anywhere near your eyes is a very bad idea. Safety glasses are a must when working with high voltage, and for this project UV blocking welding goggles might be even better.

-- This project deals with high voltage. That means that there are multiple opportunities to zap yourself (perhaps even lethally) if you are not careful. Before adjusting something, always unplug everything and discharge any capacitors. If you have a weak heart or you have a pacemaker, be super careful or consider skipping this project. Make sure to insulate everything properly and practice common sense. As an extra barrier, use a pair of rubber gloves.

-- The spark gaps in this project could cause interference that might screw up electronics nearby, and the high-voltage power supply could also damage stuff plugged into the same circuit. Consider running the laser on its own outlet circuit away from anything that you don't want to fry. You might also want to remove cell phone-like devices from your pockets, just in case.

-- Ventilation is a good idea. The spark gaps produce lots of ozone that you really don't want to inhale. Plus, I find that fresh air always makes me think better.

Step 3: Tools

Tools:

– Scissors. These are useful for cutting foil, paper, plastic sheet, and wire.

– A permanent marker. For marking out measurements. I personally like to use a sharpy.

– A ruler or measuring tape. For making the measurements.

– Tape. This keeps everything together.

– Sandpaper or a file. This is essential for smoothing the electrode rails.

– Various tools also help a lot; a pair of needle nose pliers is incredibly useful.

Step 4: Safety Supplies

Safety Supplies:

– Thick rubber/nitrile gloves. I got zapped once. Getting zapped hurts. A lot. Now I wear these.

– Safety goggles. I haven't lost an eye yet, and these have certainly prevented potential lose-an-eye situations. They also filter out a bit of UV, which helps to prevent welder's eye.

– Screwdriver. This is handy for discharging the capacitor when you are about to adjust stuff. Use it by placing the metal part of the screwdriver across the spark gap, or in any other way that connects the top and bottom plates of the laser.

– Power strip. I used this to safely turn the laser/power supply on and off. The power button on my supply was awfully close to some other parts that floated at high voltage, so I decided to use this as a switch. The strip also has a fuse and circuit breaker in it that can help to prevent all kinds of electrical accidents.

– Fire extinguisher. Just a good idea in any experimental situation, especially those that work with electricity or fire.

Step 5: Supplies

Supplies:

– A high voltage power supply.
Preferably DC (although AC will work if you can rectify it). This needs to be able to charge the capacitor plates up to at least 4 Kv. I used the insides from an old air ionizer, but many of the hv supplies featured on this site will work too. I've even read about a guy that used a Wimhurst machine to power his laser.

– A solid, insulated piece of something flat to build your laser on. Wood works, but glass or fiberglass would be better. I built mine on a wooden desk, which probably wasn't the best idea. The dimensions of the base should be big enough to leave space around the circuit, depending on how big you make your laser.

– Lots of aluminum foil. These will become your capacitor plates. Regular kitchen foil works fine. Thinner stuff works better but is harder to cut and tape without tearing.

– Plastic sheeting. This will become the dielectric of the capacitor. Anything thin and very insulating should work. I've heard of transparency sheets, Mylar, political signs, “For Sale” signs, and documents sheet covers used for this purpose. I used Mylar here.

– Thick copper wire or a resistor. This is used as a DC path across the top plates. Either works; the wire can be made into an inductor, or the resister can be taped directly onto the setup. However, I find that the wire tends to be better because the resistor heats up after a while.

– Angle aluminum (1/8" thick) or something else conductive with an even, straight edge. This becomes the rail electrodes that run parallel to the discharge channel. You will need 2 equal lengths for each electrode. My electrodes were 10 inches long. Make sure you sand out any burrs on the edges, and file or sand corners until they are rounded (see picture).

– A spark gap assembly. This functions as a high voltage switch. The design is limited by your creativity. I used US coins; 2 quarters and 2 pennies worked just fine. If you decide to use a different method, it's would be a good idea to make the gap adjustable.

– Something fluorescent. This will be the target of the laser. Since the beam is invisible to the human eye, something that will fluoresce under UV is necessary to convert the beam into visible light. I used a pink post-it note, although even regular white printer paper will work.

– Rocks. These are used as weights to hold stuff down to insure good connections. Fishing weights and other dense objects work too, but rocks are easier to find.

Step 6: Planning

How big do you want your laser to be?
I've seen designs as small as a CD and as long as a whole room. The dimensions of the laser depend strongly on how long your electrodes are. The laser isn't horribly picky; I made my electrodes 10 inches long and then estimated the rest of the measurements from there. If you decide to wing it too, you should have no problem if the capacitor to electrode size ratio stays roughly the same.

If you want to build yours exactly like mine, here are the numbers:

Electrodes (angle aluminum) -- 10 inches each
Bottom capacitor plate -- 12" by 12"
Top capacitor plates -- 10" by 5" each
Dielectric -- 17.5" by 11.5"

If you decide to experiment and find a size that works even better, I'd love hear what you've found.

Step 7: Construction

Carefully measure your foil and dielectric (the plastic sheet) and cut everything out. The foil can be a pain in the neck to cut; try to keep the edges as as straight as possible. You can tell from the pictures that I'm not much good at this.

Measure out your electrodes (the angle aluminum) and cut them if they're not already the right length. Try to avoid bending or denting the aluminum as this could lead to poor electrical connections later.

Step 8: Making the Capacitor

1. Lay down the bottom capacitor plate onto your base as shown. If you haven't picked an immovable object as a base (unlike me), leave a good margin from the edges to give you a place to grip the laser when you want to carry it somewhere.

2. Tape down the dielectric on top of the bottom capacitor plate as shown. Let the dielectric completely cover 2 sides of the bottom capacitor plate (with a margin to prevent arcing) and leave one side of the plate exposed. This bare area gives you a place to attach the spark gap. On the remaining side, leave a tiny lip of foil uncovered to give you a place to attach your power supply. Alternately, you could cover 3 sides and clip your power on the same side as the spark gap.

3. Lay down the two top capacitor plates as shown (use tape if needed). Leave approx. a 1-2 mm gap between the two top plates.

Your capacitor is now finished. Check for creases or air spaces and try to even them out. The closer the foil is to the plastic, the better.

Step 9: Making the DC Path

For those using an inductor: Put 10-20 winds into a length of copper wire like shown. Using a pair of pliers and a template (such as a broom handle) can make the process much easier.

For those using a resistor: You're done! Yay!

Both methods work equally well at forming a DC path that resists changes in current.

Step 10: Assembly - Putting It All Together!

Now's the fun part.

1.Tape your inductor or resistor down, being careful not to damage the foil.

2. Put your electrodes on the top capacitor plates. Leave about a 1.5 mm space between the two for starters (You'll probably have to adjust this later). The photos show what spacing worked for me, but there's a good chance your spacing will be slightly different.

3. Put down the spark gap. Leave a 3 mm space to start, but like the electrodes you'll probably have to adjust this. Once again, the pictures show what worked for me, but you'll need to experiment.

4. Put weights on the parts that are just sitting on the laser (ie. the electrodes). This will help to maintain good contact and prevent nasty arcs from forming. I used an industrial relay and a few rocks that I had lying around, but of course anything weighty will work.

5. Making sure that your power source is unplugged, clip/tape/attach the leads from your power supply to the laser as shown. You might want to put some weights here as well.

6. Test your connections with a multimeter (if you have one). It prevents lots of trouble later.

Step 11: Throwing the Switch

Hopefully, if you're lucky, you will get first light on this step. If your laser is working, you will hear the laser fire in pulses, with a dot of light visible on your target.
Now would be the time to put your safety stuff on. Gloves are a must if you want to adjust gap distances without long pauses in between. To get an idea of what you should be seeing, watch the video. Sorry for the horrendously cruddy pictures; I lifted them from a video since I haven't taken any picture of the laser in complete darkness. Check here later for more pictures!

EDIT: More pictures coming soon, along with instructions for building this laser with a neon sign transformer or OBIT!

Step 12: WHY DOESN'T IT WORK!?!?!

Troubleshooting

Here are some tips to help you adjust your laser.

If you see bright sparks at one end of the laser: Move the rails on that side farther apart, or file/sand the rails to get rid of dents/burrs.
If you see bright sparks along the laser, but it doesn't lase: Move the rails farther apart equally, or reduce the length of your rails. I had this problem when my rails were 15 inches long.
If you see bright skinny arcs across the rails: Move the rails closer together.
If you hear a large CRACK and you get no more pulses: There's a good chance you've put a hole in your dielectric. If it happens again after changing the sheet, try reducing the spark gap distance or increasing the thickness of the sheet.
If everything seems right but you get no laser action: Try changing the spark gap distance.
If you are frustrated out of your mind: Take a break! I took a one year break on this project after failing at it for a while. Hopefully these tips will help you avoid excessive frustration.

If you have any questions, or you're pleased with your success, post it!
Also, if you enjoyed this instructable, please vote for it! I've entered it into the Make it Glow and Mad Science contests.
<p>Hi if I use a neon sign transformer 9kv 30 ma I should expect to increase or decrease the spark gap distance and also the two aluminum rods distances ? Obviously I will need a thicker dielectric for the capacitors.</p>
<p>Coumarin 540 a dye found in yellow markers when added to ethanol or other solvents like vodka emits light at 500-590 nm. This is dependent on the laser and the medium used and the concentration of the dye and the solvent. This is for a Nitrogen laser at 337.1 nm.</p>
<p>Rhodamine B when exposed to UV at 337.1 nm emits light at 600-610 nm.</p>
<p>Orange marker have a dye called </p><h4>Rhodamine B or something similar. That can emit beam at 610 nm.</h4>
<p>One of the detergents with Tide may contain (<em>E</em>)-Stilbene like 4,4&prime;-Diamino-2,2&prime;-stilbenedisulfonic acid. They can lase 400-450 nm.</p>
<p>Here is what happens when concentrated 0.05% quinnine in acetone 6% with small amount of sulfuric acid is exposed to UV at 370-375 nm.</p>
<p>The solution in the pic is 300 g VIM solution in 150 ml Acetone diluted by 2:10. So I added 20 ml VIM-Acetone into 80 ml of tap water.</p>
<p>Here some updates with 405 nm laser and 370 nm black light.</p><h4>Sodium dodecylbenzenesulfonate glow under 400 nm but not 370.</h4><p>Quinine glows over 400 nm but the cut off is 330-340 nm. Most efficient at 350 nm.</p><p>Here is a link saying that at 325 nm the quinine absorbs 60% of the energy. Potential for a dye laser??</p><p><a href="http://www.olympusmicro.com/primer/techniques/fluorescence/fluorescenceintro.html">http://www.olympusmicro.com/primer/techniques/fluo...</a></p><p>Above is more info about Dye lasers at 337.1 nm. One picture shows poor fluorescent effects at 370 nm of sodium dodecylbenzenesulfonate. It diluted by 2:10 ratio.</p>
<p>It worked the plasma is a few cm away from each door nob. Smoother and better off than aluminum foil.</p>
<p>Here i found door nobs made from metal I am going to test them with high voltage. They may be used for the spark plug.</p>
<p>I will try this with a purple laser to see if the aluminum foil can enhance the light output and how much with a light meter.</p>
<p>Here is a method that I will use to enhance the laser output of a dye laser. Of course the reflective properties depends on the color so this may work less effectively on <strong>shorter wavelengths </strong>like purple. Keep that in mind if you do this. This is due to scattering effect.</p>
<p>If you want even more efficiency you can rap aluminum foil around the beaker and allow two small slots (holes) for the laser to enter and the beam (dye) to exit. This will act as a lasing cavity mirror.</p>
<p>Effeciency of the 337.1 nm is around 80%.</p>
<p>If you are going to make a dye laser out of boro sillicate beaker 50 ml 1.2 mm thickness the efficency is only 80%. So aluminum foil and a mirror between the beaker will enhance the output by a lot.</p>
<p>Here is a diagram on how to use flat mirrors to reflect more UV into a cavity. The akuminum mirrors may enhance the output by a bit.</p>
<p>Here is some info about <strong>DYE LASERS</strong> if anyone is interested in doing that. </p><p>http://laserkids.sourceforge.net/eng_dye_laser.html</p>
<p>Flat mirrors a few cm from a ionzing effect length electrode 4-5 cm length on both sides.</p>
<p>Yeah just have flat mirrors glued to wood or something like that a few cm away from the electric plate that produces the laser. This in terms will reflect most of the beam towards the directed path.</p>
<p>Silver oxide mirrors close to the discharge of aluminum plate may WORK. Although I am not sure about it.</p>
<p>Your best bet is ALUMINUM foil or something like that which reflects 90% of UV.</p>
<p>I may be wrong with the SILVER it only will work in an OXYGEN free environment otherwise it will turn black.</p>
<p>I forgot to mention anyone who wants to use this Silver method should <strong>WEAR</strong> gloves <strong>SINCE</strong> silver nitrate can perm stain your hands and it is sort of corrosive to skin.</p>
<p>Here is a link for different metals (although aluminum isn't on it) for copper, silver, gold and tin at wavelengths 400 nm to 1000 nm. I know 337.1 nm is not on there but silver mirrors are used to reflect this type of laser beam at school. </p><p>https://www.google.ca/search?q=copper+reflective+to+light&amp;hl=en&amp;biw=1280&amp;bih=617&amp;tbm=isch&amp;imgil=L3CRCESemxZg8M%253A%253BZSjNKpakPIADJM%253Bhttps%25253A%25252F%25252Fwww.siggraph.org%25252Feducation%25252Fmaterials%25252FHyperGraph%25252Fillumin%25252Freflect1.htm&amp;source=iu&amp;pf=m&amp;fir=L3CRCESemxZg8M%253A%252CZSjNKpakPIADJM%252C_&amp;usg=__ywhY-SavMnQhK87rg9N4XAXNEa0%3D&amp;ved=0ahUKEwjdjuTl1avPAhUB5oMKHcR9CVIQyjcIKw&amp;ei=gF3oV93OGoHMjwTE-6WQBQ#imgrc=kOdrS_wvZTBjsM%3A</p>
<p>On one of the websites (SAM) they mention using two charging coils at 10,000 volts. One charging coil is placed between the top of the two capacitors while the other is between the bottom plates. I don't know if this would be more efficient but it might be.</p>
<p>which type of electrode I can use instead of angle aluminium?</p>
<p>If e-bay doesnot sell it and you live in Ontario or Quebec try Prolab Scientific. I got a 100 ml 0.1 mole silver nitrate for 25 dollars minus shipping and tax.</p>
<p>Silver metal work a little bit better but it is costly. You can place copper pipes in a solution of silver nitrate. I did this before and you can order it easly online in solution. The copper is more reactive and will coat silver on the metal. This could work.</p>
<p>I have been thinking that a 50 K ohm resistor would aborb more than 10 ma so a 1 k ohm resistor will replace it at 1 W.</p>
<p>Finally got a HAM type HV diode that lower current by 5 ma to reduce the current from 15 ma to 10 ma.</p>
<p>The 3 W 50 K resistor prevents overheating between the two 5 nf capacitors.</p>
<p>Here is a link below explaining that any resistor from 1 K ohm to 1 M ohm will work. I will try the resistor at 50 K ohm resistance for 3 W. </p><p><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/v9sKqGC3t-0" width="500"></iframe></p>
<p>Here is a failed attempt with regular didoes, etc. The voltage even at 8 kV was too slow to control the output. Thus I had to buy the 12 kV 30 ma transformer. As stated below I still require the microwave transformer diode.</p>
<p>Here is an improved design for the power supply that converts 12 kV into half and halves the current as well. </p><p>The microwave transformer must be placed first to the 12 kV transformer so that it will not cause the bread board to burn. 12 KV is too high but 6 kV 10-15 ma is alright.</p>
<p>To improve the output and reduce the current. The voltage at 6 kV 15 ma must flow through several diodes that reduces the Current by 5 ma. If the current is too high BANG there goes one of your capacitors.</p>
<p>Here is a method of converting 12 kV into approx 6 kV DC. Three high voltage diodes (*2) are used to produce single flow DC 6 kV 10-15 mA.</p>
<p>Here the first prototype. I just need a AC power supply and microwave oven (half rectifier) to convert it into 6000 V 15 ma.</p>
<p>I made a Nitrogen laser with a high powered 25 Kilo hertzs 8000 volt 20 ma supply. Even with high voltage diodes that can tolerate 100 ma and 12,000 v it did not fire at all even when the spark gap was 0.1 mm apart. </p><p>What needed is a 3 watt resistor for 12000 volts 50 Kohm and a microwave oven that converts 12,000 volts 35 ma into 6000 volts 30 ma. The thickness of the capacitors must be doubled due to the current. Power = VI. The capacitor voltage is low (6 kV) but the current is quite high 30 ma min.</p>
<p>The switching doides are ultra fast switiching diodes.</p>
<p>Apparently as long as a load is available with a full wave rectifier the voltage of AC converting into DC. For a DC power-supply the DC power must be as smooth as possible. You need if you are going to use 25 kHz range power supply a high voltage switching diodes too.</p><p>Then you must convert it from near 12,000 Volts 20 ma into 6000 V and 5-10 ma.</p><p>A microwave oven diode that can handle for my case AC 8 kV (something that is near 12 kV max DC).</p><p>VDC = 1.414*8000 </p><p>V DC = 11,312 volts.</p><p>divide by 2 = 5656 V to 6000 V.</p><p><a href="https://en.wikipedia.org/wiki/Rectifier">https://en.wikipedia.org/wiki/Rectifier</a></p>
<p>Although I have limited practice with high voltage please do this carefully and always wear gloves, have one hand in your pocket and be reminded if you mess up with a fly back or other transformer it could be dangerous or even fatal. Do this at your own risk and always research (Intensive) before attempting.</p>
<p>If a fly back transformer is suppose to be used for a long time it needs to be soaked in oil. A 24 volt power-supply with (AC) with diodes may be used to power the fly back. Note not all but most fly-back work this way into DC.</p><p>Here is the link.</p><p><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/wNmZ1xxh1G8" width="500"></iframe></p><p>Daniel.</p>
<p>Here an instructable on making a fly back transformer work.</p><p><a href="https://www.instructables.com/id/MAKE-A-HIGH-VOLTAGE-SUPPLY-IN-5-MINUTES/step3/The-Finished-Setup/">https://www.instructables.com/id/MAKE-A-HIGH-VOLTAG...</a></p>
<p>Be aware that if the suction cup part is connected to two wires that short circuit while touching the other wire over a long period of time the fly back transformer may overheat and fry its self.</p>
<p>A glass copper plate capacitor (it has to be pretty big) for 10 kV, 5 ma current but it would not rip or breakdown when overexposed to electricity compared to aluminum foil. It is not a bad price on e-bay either. Still wondering if copper would be better at 99.999% purity?? </p><p>This may work.</p>
<p>SAM said that a flyback at 10,000 volts 5 ma should work for a powersupply if it is DC.</p>
<p>I will properly go with the flyback transformer method which is already DC but I may have issue with thin wires and conductivity. </p>
<p>Another problem with the 25 KHz power-supply is that it is too quick a pulse to efficiently enter the high voltage diodes. Special expensive diodes are required. </p>
<p>However I think using a diode for a microwave transformer MAY be better as a powersupply.</p>
<p>Here is some info about trying to build a glass capacitor flat device for a Nitrogen laser using regular air at 78% Nitrogen. The person called Mark said that at 8kV-12 kV at 35 mA when doubled with a diode (HV type) would generate 12 kV to 20 kV or even higher would easily break down the glass.</p><p><a href="http://technology.niagarac.on.ca/people/mcsele/lasers/LasersTEA.htm">http://technology.niagarac.on.ca/people/mcsele/las...</a></p><p>SAM site on Nitrogen laser when I asked through e-mail said a diode DC (12 kV, 100 ma would be Ok. However a microwave diode may be need or a variable voltage device that can adjust to 0-120 volts may work. (Maybe both).</p><p>I bought through e-bay a rare but still working 8 kV, 20 mA transformer and would generate 12 kV. It must be reduced to half. </p>

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