A TEA Laser is Nitrogen Laser that operates at standard pressure and temperature. In fact, many operate using normal air which is over 75% N2. Normal air has a property known as super radiance. This means that air can produce a laser beam without bouncing light with mirrors that most lasers require. This fact saves us much time and money. Now, before we start let me give you the needed warnings. First, this laser outputs light in the UV range. This can be very dangerous for your eyes. UV protecting sunglasses can help save your eyes. Furthermore, this project uses high voltages and charged capacitors when operating. Read the High Voltage guide from the laser cutter contest for safety information and how to generate the voltage needed. I would also like to say that I figured out how to build this laser by reading many very helpful websites for the past 3 weeks. A quick search of "TEA Laser" will find most of them. I am merely assimilating this information and adding my experience as I go. I have understood laser theory for a long time but this is the first practical laser design I have worked with.
Alright, lets get started building the laser. The second file is a schematic of sorts detailing the laser
Step 1: The Electrodes
This is the most important part of the laser. Find some small strips of very straight metal. shorter strips will be easier to use later. I used some small pieces from an old erector set. Use electrical tape to make handles as the picture shows.
Step 2: The Base
find a sturdy base to build your laser on. it should be similar in width to the rails and and about 1.5 - 2.5 times longer. Sand this smooth so that it won't damage any parts.
Step 3: Capacitor Ground Plate
Now you will need to cut a piece of aluminum foil slightly smaller than the base. Use super glue in one corner so that it won't slide around. This will serve as the bottom half of the 2 capacitors this laser uses.
Step 4: The Dielectric
Now we must add the dielectric portion of the capacitors. This must serve as an insulator between the capacitor plates. In my picture I marked it with tape so it would show up but you should not do this. The dielectric should not be much thicker than a standard sheet of paper. Some people have gotten Saran Wrap to work but that is not guaranteed to work. Instead try this. First find a power supply (using the High Voltage Guide mentioned earlier (I recommend the dc fly-back transformer)) that can supply at least 5,000 volts. Attach one lead to the bottom plate we made earlier. Then set your dielectric candidate on top. Hold the other lead above the dielectric and try to form sparks. If no sparks form you have a good dielectric. Right now I am experimenting with cut pieces of plastic bottles for the dielectric. When a suitable dielectric is found place it on the aluminum foil plate and secure it. I used thumb tacks.
Step 5: Top Plates
Now we must build the top plates. cut two more foil sheets so the are about 1.5 cm smaller than half the bottom plate and place these on top of the dielectric with a little over a cm between them
Step 6: Holding It Together
I used some flat erector set pieces and rubber bands to hold my laser together :D but feel free to do what you want. This is also when you will want to set the electrode rails on the center edges of the two top plates. Remember that you will need a way to hold a wire from the power supply to a top plate. It is important that only one top plate get connected to the power supply directly. I bolted a wire onto one of the erector set pieces holding the foil in place.
Step 7: Spark Gap
This small piece of aluminum will short out one top plate and cause the laser to fire. simply slide an aluminum strip under the bottom plate and rig up something that will hold it about 3 mm from the top plate. I once again used erector set pieces for this.
Step 8: Charge Coil
this coil will allow both capacitors to charge but will act as an insulator when the spark discharges one plate and cause a charge to jump our electrode rails. Coil about 20 turns of wire and attach it to the foil top plates.
Step 9: How to Use the Laser
Start with the rails about 1 mm apart (about the thickness of a large paper clip).
Attach the ground to the spark gap of you laser and the high voltage to the coil or a top plate
When you turn on the power the spark gap should fire. If not then disconnect, ground everything and find a short.
Every time the spark gap fires look for a spark on the rails. If you can't find a spark move the rails closer. If you still can't find a spark then disconnect, ground everything and find a short.
If the rails are sparking then adjust them until the spark is jumping across the whole length of the rail. This will be a challenge that you will need to master. At this point color some paper with a highlighter and place it at the end of the rail. The ink will glow brightly with the UV beam the laser makes.
I will add pictures when I figure out how to take good pictures of a firing laser.
Step 10: How Does It Work
The 3 foil sheets act as 2 capacitors that share a common ground plate. They are charge by the power supply until the charge is enough to set off a spark and discharge the 1st capacitor. At this point the two capacitors try to equalize but the coil is sluggish because of the magnetic field it creates. So instead the electrons jump between the rails and excite the N2 atoms in the air between them. When these atoms calm down they release photons with a specific frequency and form a laser.
Step 11: What to Do Know
1. Make a bigger laser.
2. build a chamber around it and use pure N2 instead of open air for improved performance.
3. Build death bots and rule the world with your new laser cannons