Homebrew UV "airlaser"

[Seoul_lasers]

I was fooling around yesterday with a stungun... yes I know what some of you are thinking. Did I shock myself... no ...
Anyways and I got an idea suddenly. What If I used my stungun to power a small airlaser. I quickly got myself two aluminum plates simular to what posted on the website here.

Hubert's laser page: Air laser

and built a quick and dirty version. I turned it on first by feeding the stungun 5Vdc @ 800mA

I got a tiny sliver of an output put it could just fluoresce a piece of paper coated with Sodium Fluorescene (yellow highlighter).

I tried it again using 7.2v at 1A. This time the output was stronger and output voltage was around 40Kvdc. spark gap had to be re-adjusted. -- final output was marginally better.

I tried 9v at 1A and then put a 5nF 20Kvdc cap across the laser. Tesla coil style. cap discharged the gap. Finally the laser started giving me some output.

I wouldn't call my endeavors with this laser a stunning success but it did work ~sort of.

 

[Asherz]

Very nice

If I remember correctly, you can do a similar thing with a nitrogen TEA laser. (just checked your link and that's what the "air laser" is.

That requires a wood base, two sheets of foil, then a cavity and you use a shock at the end and it lases below 400nm, look up nitrogen laser and you'll get an idea of what I'm going on about,please excuse any mistakes I made, I only have a vague understand of nitrogen lasers since I only briefly read the instructions.

 

[Seoul_lasers]

It was fun for all of 10minutes, then I dismantled the unit. Got to love multi-purpose cookware. Bake'n'lase.

- oh and today I tried making a dye-laser from a camera flash. I used highlighter fluid dissolved in Vodka in a quartz tube that was used as a large flash. Pics will be coming soon. It lased very well. (better than I predicted) I used a smallish flash 6cm long and attached it with a wrap of Al foil tape. I made the other end of the dyetube reflective.

Output was a green yellow and similar in appearance to a dpss laser, with a bit more yellow.

 

[Trevor]

Got to love multi-purpose cookware. Bake'n'lase.

If you were marketing to me, that's be a major selling point, my friend.

-Trevor

 

[BShanahan14rulz]

Sweet! Tazer = laser power supply!

 

[Seoul_lasers]

Sweet! Tazer = laser power supply!

Yes, well a tazer is DC based and used a pulse discharge circuit that gives 35-60kvdc out maximum. i think a marx impulse or walter-crofton generator would be a better supply for a TEA/N2 or Airlaser....
fyi, Those 100kv rated units are NOT even close to 100kvdc btw.. not like this is a surprise or anything.

tazer = very small TEA/airlaser psu. maybe a few 10's of uWs output if that....

 

[ossumguywill]

Yes, well a tazer is DC based and used a pulse discharge circuit that gives 35-60kvdc out maximum. i think a marx impulse or walter-crofton generator would be a better supply for a TEA/N2 or Airlaser....
fyi, Those 100kv rated units are NOT even close to 100kvdc btw.. not like this is a surprise or anything.

tazer = very small TEA/airlaser psu. maybe a few 10's of uWs output if that....

I got an ebay unit rated at 2.8 million volts or something... obviously not that high, but it's 100 times better than most tazers I see in videos, a bright blue spark that is constant and doesn't just flash a couple times a second like most lame cheap ones. I'm gonna guess it sparks around 200 hertz. It can plug into mains power so I could probably use that... I also have an ignition coil lying around, a 555 timer and a high-speed relay should do the trick with that.

will

 

[StridAst]

Curious, what did you work the camera flash electronics in somewhat to power the dye laser? either way, very cool concepts

 

[BShanahan14rulz]

wouldn't any power supply capable of charging the HV cap be ok? I thought it was the quick discharge of the cap that was important in an open-air laser.

I'm actually surprised there aren't more threads about TEA lasers here. Well, ok, so it's laserPOINTERforums, but it's still a really cool DIY laser that costs $0! well, wait, how much is aluminum foil? and where's that broke smiley when I need him!

 

[Seoul_lasers]

I got an ebay unit rated at 2.8 million volts or something... obviously not that high, but it's 100 times better than most tazers I see in videos, a bright blue spark that is constant and doesn't just flash a couple times a second like most lame cheap ones. I'm gonna guess it sparks around 200 hertz. It can plug into mains power so I could probably use that... I also have an ignition coil lying around, a 555 timer and a high-speed relay should do the trick with that.

will

Your tazer sparkgap is set to fire at less than the full charge of the capacitors rated ability. That's my guess.

My tazer runs 6v but I feed it with 7.2v with about an Amp of current for short durations. The output is around 60kv - 65Kv with near continuous sparks at 6.5-7cm of point to point distance. The transistor is really heating up so... I am careful.

Btw, about the Ignition coil setup. A dual Ignition coil setup can easily output 80-100Kvac or Kvdc at 10's of uAs when properly modded. One fellow over at the 4HV group holds the world record in overvolted ignition coils. His record stands at 250Kv at 1mA, or just about 2.5Kw. His name escapes my memory.

Your 555 timer will work well for DC at low current but I'm recommending skip the relay and use a transistor and heatsink or SDIAC (light dimmer). There are lots of examples of decent HV circuits over at www://4hv.org and this page below

High_voltage supplies

 

[ossumguywill]

^how do you use only a transistor and a coil? Isn't that how that "joule thief" circuit works? I fail to understand how these coils behave.

 

[Seoul_lasers]

wouldn't any power supply capable of charging the HV cap be ok? I thought it was the quick discharge of the cap that was important in an open-air laser.

I'm actually surprised there aren't more threads about TEA lasers here. Well, ok, so it's laserPOINTERforums, but it's still a really cool DIY laser that costs $0! well, wait, how much is aluminum foil? and where's that broke smiley when I need him!

Well not quite. IF you want a quick and dirty laser with nWs or something go for it, but if you want to give you some measurable or useful output it's going to cost you a fair bit more than $0!

 

[Seoul_lasers]

^how do you use only a transistor and a coil? Isn't that how that "joule thief" circuit works? I fail to understand how these coils behave.

Confused... not sure what you mean.

You need a strong power supply to run an SDIAC or Transistor.

I'll either run the SDIAC from mains (115-120vac) or a 12v-24vdc source with the transistor setup. In the SDIAC setup I use a Capacitor 1-10uF to control the mains current. Output of this setup runs 400Vac at 600Hz into the coil! In the DC version of the setup I use a battery charger on 5 to 10A setting. Transistor MUST be mounted on a heatsink or it will burn up.

Use the I gave to you to see what I am on about in the previous post.

 

[Mattis]

I believe I once heard that high power UV lasers ionize the air. Does that mean that electricity from something like a tazer could follow the path of lasers to make a wireless tazing device?

 

[Seoul_lasers]

In theory yes, in practice this has failed miserably. So, not realistic with current technology.
Btw, this was done with not UV lasers but LWIR (CO2 and I2/O2 laser systems).
charge density and ionization couldn't ionize the air reliably enough to conduct a charge.

 

[Benm]

Something like that has been pursued for ages, but never found practical application.

The laser power required to cause air breakdown and the ionisation channel required is simply too great. Any laser capable of doing that would be a potent weapon in its own right, and probably not require the tazer part to be effective.

There is no need for UV lasers to do any of this - near-IR lasers like pulsed 1064 Nd:YAG units can cause air breakdown just fine - but at power levels that pose a very serious hazard... not only in terms of eye damage, but also of setting things on fire.