How to Build a T.E.A. Laser




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

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    7 Discussions


    2 years ago

    Here another video on how to make a dye laser.


    2 years ago

    Here a thought make a dye laser out of dish washer powder or yellow marker dye with either a Nitrogen laser or a 405 nm burning purple laser.


    2 years ago

    I have built both a Nitrogen laser at home using 0.1 mm thick glass electrodes but could get a transformer or a DC high voltage diode. I have built a TEA Nitrogen laser for School in the Photonics Engineering Program. It produced 0.5 to 1 W of optical power 337.1 nm.


    5 years ago on Step 11

    yeah! rule the world is the mest part! hahahahaaa!


    8 years ago on Introduction

    I love the simplicity of the design. Many years ago I tried to build one of these from a Scientific American article, but got hung up on the difficulty of getting pure nitrogen gas (I was just a kid then). Using plain air, with no enclosure... can't get much more basic than that. Nice job.

    Dream Dragon

    8 years ago on Introduction

    Couple of pointers

    The Rails need to be SUPER smooth and Super Parallel. Any unevenness or sharp points will cause the discharge to concentrate instead of spreading allong the length of the cavity.

    Use multiple layers of plastic in your Dielectric. This way any weak spots in one layer are less likely to line up in another layer. Two or three thin layers are better than one thick one.

    The Washing Powder trick is a good one, as is the Highlighter ink. You can extract highlighter ink and I have heard of it being used as a Lasing medium in itself with this type of UV laser as a PUMP.

    Good luck with your experiments and DO take care with High Voltage and High Energy experiments, especially as this machine emits a highly concentrated beam of INVISIBLE radiation.