Home Made T.E.A. Lasers

unbelievably simple

[Nyle] was interested in building lasers at home but felt that the exotic parts list was just too daunting. That was, until he discovered T.E.A. lasers. T.E.A. lasers can be constructed from a few bits of aluminum and some high voltage. They emit UV light, as you can see in his examples where he shoots them through a jar full of water with highlighter ink mixed in.

He has posted several variations of different sizes as well as numerous images of them in action. You can see a video of one in action after the break. We also have to point out the fantastic music in the video. It reminds us of those school videos left over from the 50s.

[via Makezine]

46 thoughts on “Home Made T.E.A. Lasers

  1. A parallel row of razorblades or a pair of saw blades may work better. The high curvature from the very sharp edges will concentrate the electric field.

    I enjoy the laser stuff, thanks for listening HAD.

  2. WOW … i have loads of HV equipment i gota try this … as soon as i get a good pare of UV goggles XD

    why must every one complain when something was posted long after it came out? do you really expect HaD has a team of people searching every corner of the web every day?

  3. This is pretty awesome. I’ve considered making one of the simple nitrogen lasers, but this looks to be much easier and really neat. I have a good number of HV power supplies that I rescued from my college chem lab’s basement that can be used.

  4. This is one of the simple nitrogen lasers. TEA stands for Transversly Excited Atmospheric. There are plans in Scientific American Aamateur Scientist of June 1974 to make this exact same laser. The same basic design is also use for some CO2 lasers and Excimer lasers.

    Just about any pair of goggles or glasses will absorb 99.9% of UV.

  5. 99.9% of UVA, UBV and UVC? If you have 1000 watts of laser and “any pair of glasses stops 99.9%” then you still get seared with 1 watt of laser. 1 watt of laser power will pretty much instantly destroy your retina. Most laser pointers are 0.1 milliwatts (mW). So about 0.001 watts. It would take 1000 of those to equal the power of 1 watt, all else equal.

    “Swiss doctors reported a case of a boy who bought a 150 mW laser, sold as a “laser pointer,” which left him temporarily blind in one eye, and with 20/50 vision in the other eye, after he shined it in a mirror. The boy’s vision eventually returned to near-normal.”

    A 1 watt laser is considered a Class 4 Laser.

    Class 4 lasers include all lasers with beam power greater than class 3B. By definition, a class-4 laser can burn the skin, in addition to potentially devastating and permanent eye damage as a result of direct or diffuse beam viewing. These lasers may ignite combustible materials, and thus may represent a fire risk. Class 4 lasers must be equipped with a key switch and a safety interlock. Most entertainment, industrial, scientific, military, and medical lasers are in this category.

    You can cut (as in separate) non metallic things with a 20 watt CO2 laser, with considerable speed. That includes meat, plastics, etc.

    Extra bonus – a UV laser isn’t really “visible” in the sense that a “normal” red laser is. I don’t want to sound reactionary and overly safety oriented but lasers are serious hazards if used incorrectly so proper safeguards and precautions should be taken prior to their use.

  6. “Most laser pointers are 0.1 milliwatts (mW). So about 0.001 watts. It would take 1000 of those to equal the power of 1 watt, all else equal.”

    Can’t do math today it seems. 0.1 mW = 1/10000 watt. 0.0001 watts. So 10,000 laser pointers to equal one watt.

  7. @CutThroughStuffGuy

    every less than $5 laser pointer i have ever gotten says there 1MW not 0.1MW
    normally red laser pointers are 1MW green laser pointers are 5MW and blueray are 20-100 i believe

    i have never seen a 0.1mw laser and i cant find any on google for sale

  8. @biozz I sincerely doubt that it’s MW (MegaWatts). Industrial lasers don’t even get that high. The average laser pointer is somewhat less than 5mW, getting up to 100mW, with the ones close to 100mW able to cause permanent eye damage. blu ray is around 30mW laser

  9. @Squirrel
    when you talk about personal lasers unless otherwise specified mW spelled mw Mw mW or MW always means MilliWatts
    i thought everyone would have understood that but i forgot i was not on a laser forum sorry about that

  10. @ CutThroughStuffGuy

    With the short pulse time of one of these lasers the average power is pretty low. Plus UV does not penetrate material like the longer wavelengths do. If you have a UV laser that is powerful enough to do any damage, like my big excimer, it ablates the surface and does not penetrate deeply. This is why excimer lasers are used for LASIK eye surgery.


    Flourescent dyes will lase with a nitrogen laser. “TEA” is just the excitation method, not the laser itself. These are also known as atmospheric nitrogen lasers. They require little in the way of a resonant cavity and will work without mirrors but they are more efficient with. Even something as simple as microscope slides works well for cavity optics. One other thing is that N2 lasers do like to be ran at slightly below atmospheric pressure.

    You can also get an old excimer from a lasik machine and run it on nitrogen instead of the nasty excimer mix (Usually Argon or Krypton and Fluorine). They do run at about 3 atmospheres in the chamber.

  11. Industrial lasers generally run 1000 – 4000 watts.

    Those can cut through half inch aluminum or an inch (or more) of steel.

    Even if laser pointers are 1 mW, they are still vastly lower in energy than industrial lasers.

    But even 5 Watts could be seriously damaging.

  12. “This is why excimer lasers are used for LASIK eye surgery.”

    That makes sense. But commercial, medical excimer lasers tend to be well defined relative to their power – tightly controlled and with known tissue responses and proper safety interlocks.

    I worry, I hope correctly so, with any “homebrew” laser – UV or not – that proper protections need to be taken given the incredible potential for severe injury in such a short period of time.

    I don’t want to discourage people who truly know what they are doing from working with UV lasers. But they need to understand what they are getting into BEFORE they start working with high powered lasers. And by high power, I mean pretty much anything over 1 milliwatt to err on the side of safety.

  13. All you safety whiners are the reason kids don’t have chemistry sets anymore; for christsakes, just fuck off already. If people want to be dangerous with dangerous things, they’re allowed to.

    That said, awesome hack. I love projects like this where all the components are relatively cheap and simple, yet the result is still impressive.

  14. This laser IS in fact capable of MW (yes, megawatt) output, but you have to know the repetition rate (it’s pulsed, not CW), average power, and the width of the optical pulse. These are usually in the neighborhood of 100ns at 1 pulse / second.

    C’mon people. read.

    And I have to agree with @Devin. Have fun and learn things the right way. Don’t just give a kid a laser pointer. A polycarbonate face shield is adequate to keep *stray* UV (at 248nm from a KrF excimer) out of your eyes. If you were to look into the beam directly (which they tell you not to do ANYWAY) with a pair of goggles on, then you probably deserve to be blind.

    From Wikipedia:

    “These first “Pin-Bar” TEA lasers, operating at around one pulse per second, were easy and cheap to construct. By operating at atmospheric pressure, complex vacuum and gas-handling systems could be avoided. They could produce MW peak powers of a few 100 ns duration capable of breaking down air if brought to a focus with a short focal-length lens. Disadvantages were poor gain symmetry, dissipation in the resistors and size.”

  15. Been wanting to build one of these since I read the Scientific American article back in college in 1980.
    As I remember the article mentioned the possibility of reflecting the beam off of clouds and using it for communications. If the repetition rate was high enough you could use it to transmit Morse or possibly use two repetition frequencies to transmit binary data.

  16. Uhm, did anyone notice that TEA lasers are technically not even lasers? This thing does have the gain medium but not a resonator, and what we see is called amplified spontaneous emission, or superluminescence. The light that comes out of it is not coherent in the least.

    Still, these things are simply fun to play around with :)

  17. A very cool project, and yes THAT’S the science-y music perfect for such a demonstration.

    I almost expected to hear Dr. Julius Sumner Miller start to expound on the subject.

    -for science was his business…

  18. By way of encouragement, the power requirements of TEA lasers like this are practically identical to the needs of a tesla coil. Two projects for the price of one, and a weekend spent coil winding! I first heard about this sort of laser reading about tesla coils; the design there involved a simple chamber around the electrodes with bottled nitrogen gas being blown into one end. This should allow for faster pulse rates and possibly higher powers as oxygen poisons nitrogen lasing.

    Safety wise, you’re significantly more likely to fry yourself using the HV power supply than you are to blind yourself with the laser. Also, I’m not totally certain that UV lasers will necessarily induce permanent blindness due to all the beam energy being absorbed by the front of the eye; you’ll get some nasty photokeratitis and potentially permanent corneal damage but that’s the sort of thing that can potentially be fixed by surgery (unlike retinal damage from visible wavelength lasers). Don’t take my word for it though.

  19. nice project !
    This is one of those projects perfect for an old microwave oven transformer, most of them are in the 4KV range , have a diode matched for the voltage , and even a capacitor if you need it. People always look at me weird for picking up peoples old microwaves off the curb or trash. Those parts inside are awesome for HV experiments and the transformers alone are worth the time.

    For dielectric check out baking supplies. They make silicone sheets for lining baking trays for large sheet cakes. These are not the thicker ones made for re-use but disposable so are really thin. Sizes easily available are 16 x 24″, 30 sheets for $5

    Another option is using plain clear silicone caulking. Put some cooking oil on two pieces of metal . Put a bead of the silicone down the middle of one piece and put the other piece of metal on top. Weight it down or stand on it to flatten it till the silicone squeezes out. Let it dry then pull the metal apart and you will have a paper thin sheet of silicone for dielectric.

    For rails try copper water pipe. It is very hard, straight and two pipes placed parallel have an almost perfectly straight path for the spark to jump across. You can also solder the plate directly to it if you use copper plates for the base.

  20. Very interesting project but I can’t figure out where the beam is emitted? From the end, parallel to the bars? The author does not mention where it lases from in the text, or indicate it in his diagrams.

  21. About CO2 laser safety.

    I’m working at the Technical University of Denmark. We used to have a 9kW CO2 laser in our lab.

    It was located inside a cubicle built with regular single-layer window glass. This to absorb stray reflections and diffuse laser radiation that would otherwise be harmful for bystanders.

    This cubicle was certified as a proper class 4 laser protection.

    Stray laser light could be in the region of several watts. This is more than I expect for a homebuilt T E A laser to put out.

    So if you should want to replicate this build and you want to be on the safe side, then take a regular sheet of window glass and use that to protect yourself from stray laser light.

  22. Oh btw. @Squirrel

    Many industrial lasers do in fact reach the megawatt range. These are however not continuous wave lasers such as CO2 lasers as used for sheet metal cutting.

    We’ve got an industrial nd yag laser in our lab that outputs several megawatts when q-switched. (pulsed)

  23. @biozz It’s because HAD will post stupid drivel of some idiot that glued a knob on his Radio and calls it a hack, and the real hacks/builds like this do not get up there for quite some time.

    I understand they dont pay their editors much more than what you can get at burger king, but they can spend that time searching for cool things or “GASP” taking something like this and writing up a DETAILED HOWTO with the theory and everything else clearly explained. Or continue it further like linking to the materials needed to change from UV to visible light. etc…

  24. David: STRAY UV laser light. window glass wont stop anything BUT UV.

    you need to qualify your statements, most readers here do not understand 1/90th of any subject.

  25. neat hack.
    interesting to note that the early TEA lasers could achieve air breakdown..

    wonder if any interesting effects can be generated by using a pulsed >100mW bluray diode focussed along the axis to encourage ionisation of the gap?
    i’d expect the output power to increase somewhat.

    as for goggles, the ones sold online for use with bluray diodes ought to work, failing that its welding goggles time.
    (first test with a “safe” uv source such as an LED to confirm that attenuation is below the Class 1 limit, I learned that the hard way!!)

  26. @fartface

    Woops. I should read the original article a bit more thorough before posting should I not? :D I somehow had managed to persuade myself into believing the output was IR.

    A piece of glass would not do a thing to UV light, only the far-ir light from a CO2 laser.

    I succeed in failing. :)

  27. @devin, why don’t YOU f-off already! who the hell
    appointed you the spokeperson ? the warnings being
    discussed are legitimate and certainly should be
    taken heed of.

    as for chemistry sets/kids, yeah genius, let’s see
    you give an 8yr old some concentrated sulfuric acid
    and maybe some liquid mercury to play with.

    some degree of safety & caution is mandatory. you
    ignore risk at your own peril. if it’s you alone,
    who gives a fuck ? if you’re being an enabler for
    someone’s kids and providing them dangerous toys
    to screw around with, and no information on the
    potential hazards, it’s the height of reckless &

    and i wish people would lay off with the “that
    said” bullshit. most overused term in the english
    language lately!

    last wise guy i knew who downplayed safety
    became a “crispy critter” when he got in the
    arc zone of an industrial HV switching panel.
    it was not pretty (and you never forget the

    1. @all,
      yes, lasers are dangerous, be careful. So are the tools you will use to cut the aluminum, also that high voltage power supply. So be careful with all of it.

      There, now both sides can stop bickering. Stuff is dangerous, sometimes we should be reminded. no need for any personal fighting.

  28. @CounterPoint

    You mad :3

    Anyways, what I’m trying to get across is nobody important actually pays attention to what you’re saying. Nobody’s going to read some whiny rant about safety precautions and go “oh no, guess I shouldn’t make that death-ray I’ve been working on.” The people who like to build those things aren’t going to listen to you, and the people who do listen are probably too scared of things like laser pointers and mains voltage to ever do anything more than blink an LED with an arduino.

    And yes, let’s give kids sulfuric acid and mercury; liquid metal and acid that can instantly turn sugar into carbon are pretty awesome, and might actually get them interested in chemistry. Sure you could burn the hell out of yourself with the acid, but humans are generally pretty good at recovering from that sort of thing. I mean think about it, you’d have to actually drink either of those chemicals to do yourself any sort of irreversible harm. You’re not going to keel over just from being in the nearby area without gloves and goggles on, like some people seem to think.

    Your “think of the children” mentality is what’s wrong with the world today. Safety should never be the primary concern; once you head down that route, it’s not long before everything is sanitized and childproofed and really goddamned boring. I’d rather be injured or killed trying to do something awesome, than to never have tried to do anything at all.

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