DIY Home made High Performance TEA Nitrogen Laser and Dye Laser!

Episode 5
#laser
#optics
Check out my other videos: / leslaboratory​
Please don't forget to like,subscribe and comment for more great content!
If you found this content useful, and would like to support this Channel, please consider supporting this work on Patreon: / leslaboratory
Or donate directly: paypal.me/leslaboratory
Alternatively, please share this content on your social media platforms, it really helps me out!
In this video, I show three of my high performance designs for Home made TEA nitrogen Lasers.
Although Nitrogen Lasers are quite simple to build, they are difficult to build well. My first ever TEA Laser was held together with gravity and glue. The ones demonstrated here are worlds away from those first attempts!
The two Charge Transfer Lasers demonstrated, have high repetition rates, high output powers (peak and average) and are robust, with many thousands of shots possible before the dielectric has to be replaced.
These can easily drive a Dye Laser to threshold, in fact the peak power is so high, Dyes can be Lased Superradiantly (Feedback is so high, no mirrors are needed!)

[@thethoughtemporium]

That. Was. Amazing. What a phenomenal improvement to the usual TEA laser setup

[@LesLaboratory]

Thanks very much. Best of all, there is nothing particularly exotic in the builds, except perhaps the doorknob caps!

[@acompletelynormalhuman6392]

You could make a more powerful TEA laser using this design and then make you even more Quantum entangled particles

[@LesLaboratory]

@@acompletelynormalhuman6392 One is in the works at the moment with a 30cm long channel, just waiting on parts arriving. They tend not to scale up particularly well from what I understand, but we will see how it goes!

[@Jonodrew1286]

I second that - my output was pretty good, spark pulse felt like it was in sync with the nerves in my teeth and UV dot was not too shabby - though I have to admit it was massively Heath Robinson - shame I cannot up load any video here! 😅😅

[@1islam1]

@@LesLaboratory ⚠️ God has said in the Quran: 🔵 { O mankind, worship your Lord, who created you and those before you, that you may become righteous - ( 2:21 ) 🔴 [He] who made for you the earth a bed [spread out] and the sky a ceiling and sent down from the sky, rain and brought forth thereby fruits as provision for you. So do not attribute to Allah equals while you know [that there is nothing similar to Him]. ( 2:22 ) 🔵 And if you are in doubt about what We have sent down upon Our Servant [Muhammad], then produce a surah the like thereof and call upon your witnesses other than Allah, if you should be truthful. ( 2:23 ) 🔴 But if you do not - and you will never be able to - then fear the Fire, whose fuel is men and stones, prepared for the disbelievers.( 2:24 ) 🔵 And give good tidings to those who believe and do righteous deeds that they will have gardens [in Paradise] beneath which rivers flow. Whenever they are provided with a provision of fruit therefrom, they will say, "This is what we were provided with before." And it is given to them in likeness. And they will have therein purified spouses, and they will abide therein eternally. ( 2:25 ) ⚠️ Quran

[@andreithe3893]

"you can make it yourself" says the guy that makes commercial lasers. Just discovered the channel, love it

[@LesLaboratory]

You can! These are not commercial, designing and building them for me is just a hobby :-) My day job is with Computers. Glad you love the channel, more cool stuff is in the pipeline for electronics/science/computing fans!

[@sto2779]

This is the only professional nitrogen TEA Laser I've seen on the internet for DIY...

[@LesLaboratory]

Thanks! Glad you like it!

[@johnnycash4034]

There's another channel...i think it's rocket laser or something. He is pro

[@LesLaboratory]

@@johnnycash4034 Yes, Swissrocketman. He designed commercial N2 Lasers for CERN!

[@Ilovekatjalel]

After watching the video, I wanted to assemble this design. The idea of using a spark gap with air removal is especially interesting.

[@hullinstruments]

Thank the Lord! Finally another channel on KZbin with some great laser content!

[@LesLaboratory]

Yep, there should be more on here! Thanks for your support! :-D

[@pakoyones]

Amazing and jaw-dropping to watch and listen to you! Thanks once again Les, not only you are inspiring but your explanations are crystal clear and very entertaining and full of insight. Just Perfect.

[@FilterYT]

Great job, thanks for sharing!

[@Barc0d3]

I CAME.... to appreciate your knowledge and passion! Love your videos!

[@SimonSozzi7258]

That's sick!

[@henrikstenlund5385]

Great job Les

[@hullinstruments]

Hope to see more DIY tea/nitrogen stuff soon! Your channel has become one of the best and my most favorite! It’s the only channel that’s inspired me to work on my own projects in a very long time

[@LesLaboratory]

Awesome thanks! There is yet another Nitrogen Laser video in the works...

[@hullinstruments]

@@LesLaboratory can’t wait! You’ve got me interested and motivated… I’ve had the chance to get into this stuff before and never did… now I’ve caught the bug!!

[@ph08nyx]

It's fantastic!

[@LesLaboratory]

Thanks!

[@chanheosican6636]

Build a professional TEA 2W Nitrogen laser so seeing those mini lasers with capacitors was very cool.

[@edgeeffect]

I love your plumbing fitting spark gaps.

[@LesLaboratory]

Thanks! The good thing about constrained by a micro budget is knocking zeroes off of the prices of commercial equivalents!

[@AndreiBres]

Great video!

[@LesLaboratory]

Thanks!

[@Bianchi77]

Nice info , thanks :)

[@raymondzhao9557]

This is really cool！

[@robertbass4590]

Found your channel just recently. Really awesome video here. I built the SA type version of the TEA N2 laser in junior high MANY years ago. I got a huge kick out of this video (and the dye pumping finish was super). The aluminum hex bar extrusion is such a good idea. I imagine the edge tolerances are great for the purpose.

[@LesLaboratory]

Thanks! Yeah, I built the SA one too (except with doorknob caps). I actually still have it in my cupboard, along with a copy of "Light and its uses". There is nothing more satisfying than building something like this truly from scratch. I tried a number of profiles (I now have a whole box of various shapes), but hex had the best performance and was above all easily repeatable. Edges aren't bad, but I give them a light polish with 000 grade steel wool before use. Long pieces bend a little, it would be nice to be able get flat bar with a 120 degree knife edge on it instead. Cheers!

[@dalenassar9152]

@@LesLaboratory I heard that the N2 laser...fron "light and it's uses" & from "the amateur Scientist" (Scientific American) Can't work properly due to the high inductance of the thick insulation between the copper. It was also copied and sold as "PLANS" by 'Amazing Devices' This guy even used the same sketches...

[@fredmercury1314]

20:30 Also... There is a smiley face.

[@susand9881]

Thanks! Educational and entertaining at the same time (in a science geeky kind of way). 😃 26:00 Amusingly, YT auto-captioning took the discharges as [Applause]. Quite apt, though! 😆 BTW, since the gas feed is set up, it may be interesting to try gases other than N2. Regarding the dielectric sheet, often they may have tiny imperfections, creating weak spots, where breakdowns eventually occur. The usual measure to mitigate these to have 2 or even 3 layers of the dielectric, layered together. That is, 3 sheets can perform more reliably than 1 sheet of 3 times the thickness.

[@LesLaboratory]

Thanks! Regarding the dielectric, this is solved by redesigning the circuit, such that it is not under permanent stresses (charge transfer scheme). Alternative gasses are in the works, I have optics for this on order, and manifolds in my basket 😉

[@susand9881]

@@LesLaboratory , impressively quick answer to a comment on a video posted 3 years ago! 😃 Standing by for watching more laser experimental goodness!!

[@teslasintern]

Is nobody else going to mention that his dyes have little smiley faces on them?

[@LesLaboratory]

LOL I noticed that in post, there are 2 printed squares either side of the label and the meniscus is the smile. They are happy little dye cells!

[@teslasintern]

@@LesLaboratory Haha! "They thought we wouldn't notice, but we did."

[@ingolorenzo4158]

The British guys like the tea laser

[@LesLaboratory]

Can't start the day without good tea!

[@andymouse]

Fantastic ! just found you and subbed, built a Nitrogen laser many moons ago very primitive but did Lase, been in love with laser light for as long as I can remember (like a lot of us ! ) gonna check out your other vid's hope there is a schematic for your power supply's there...cheers !

[@LesLaboratory]

Yeah, it's addictive! There is a video here of the PSU: kzbin.info/www/bejne/fZO0dpSkacyqja8 no diagram, but a real easy straightforward build! Thanks for your sub!

[@omsingharjit]

I think it deserves video explaining advantage and disadvantage of this laser

[@jimparsons6803]

Really amazing work. I gather that this fellow might be a chemist for his access to the cuvettes? Very common tool for FTIR work.

[@ted_van_loon]

had the same problem as the first shown design with my diy transistor, used a to thin dielectric so eventually it burned through it.

[@PhilipLeichauer]

If you've got it running with a little corona in the dark, try squirting it with some canned air. Make sure it's the refrigerant type and not flammable. The former should suppress the corona nicely and the latter make everything more warm and orange. The refrigerant type should be interesting to try in the pressurised spark gap.

[@LesLaboratory]

For sure. It would be interesting to try SF6 as well.

[@Jonodrew1286]

Much sturdier design - has given me some impetus to build a better one.....

[@carlobuongiovanni7934]

Very powerful, could it burn if focalized on the target?

[@n8lbv]

Do you have any videos that explain the square "bottles of dye" or what look like this? I don't understand the beam coming out at 90 degrees from the beam going in. If these are simple glass containers and if the inner glass surfaces are actin as the partial mirrors on each side of the lasing liquid. Or maybe there is a mirror off camera or housed in the assembly holding the fluid. And am guessing there are mirrors or something in the dye containers that I am missing. Thanks.

[@SenpaiSkyy]

14:54 Unreal Tournament 2003. I see you are a man of culture. 😎😎😎

[@LesLaboratory]

Of course! :-)

[@dreamyrhodes]

This is really cool! Subscribed Anyhow a question: Does the spark gap produce much EM-noise in radios or TV? If yes, could that be shielded easily? With a metal case or something maybe?

[@LesLaboratory]

Awesome thanks! Yes, spark gaps (and even semiconductor switched Nitrogen Lasers) radiate loads of EM-noise, so an analog radio or TV, will 'pop' or display static. It will interfere with digital equipment as well. If this was built into a metal case including the PSU, you can easily minimise the interference significantly. After that, you may have to add line filters or ferrites to the input power leads to minimise leakage that way as well.

[@roccomarasco216]

When I was young, I was very curious about everything what's new in the field of laser technology. my first device was a helium neon laser from Conrad Elecronic in Germany. it cost 400 German marks at this time. not to be compared with laser pointers for a few DM, which were available on every rummage table a short time later. but I had never lost my interest of this cool hobby. you rarely get useful offers on eBay that can be paid for and are still useful. I just googled what a laser cuvette costs. 338 euros for one peace... unbelievable... Thank you for your amazing work. 👍

[@LesLaboratory]

Thanks! Yeah eBay prices for these things can be insane! You can get Quartz cuvettes from China for around 35 Euro that are usable (though they leak over time as they are frit-bonded). Fully fused quartz cuvettes can also be had from China for about 100 EUR.

[@roccomarasco216]

@@LesLaboratory ah, many thanks for this useful Information. Maybe I bye some for my own experiments. I have to laser dye from the past.

[@mltoob]

How does the cuvette for the Rh6g become directional without silvered windows or mirrors?

[@MathewMoss-fp9ju]

I would make a modification to this if I had the resources laser the UV laser to a GAGG crystal and set up optics to excite the GAGG to lase and hopefully get a bright yellow beam.

[@florinpetrache7834]

i like to see in action nitrogen laser from this clip (with double capacitor).

[@pakoyones]

Just thinking in using my old 500pf sprague doorknob capacitors. They are 5, so would it be a good idea to use one of them as peaker (for a 9cm ca laser channel) and the other 4 as dumper? According to the facts you talk about in your videos, it should be 60pf peaker for each cm of laser channel and dumper has to be 3-5 times peaker's capacity if I remember well... Thanks!

[@rezatavan5048]

❤❤❤❤

[@graealex]

This video is a good example btw. RE color coordination, you got the outside light shining in with 6000K at noon, the overhead lights have around 3000K, and because of the harsh shadows from the bright outside light, the camera is constantly pumping because of exposure changes when you move your hands around. Solution would be to completely block out the outside light, have your overhead lights at 4000-5000K, have the whole setup on a table, best is a light-gray background/surface, and some additional directed lighting at the same color temperature. Other improvements would be to put up the schematics as CAD/EDA drawings. Marco Reps for example often shows SPICE animated simulations. Unless you can pull off hand-drawn schematics as good as Big Clive.

[@LesLaboratory]

Thanks again. I have ordered a couple of small 5600k lights for close up work and consulted the camera manual re white balance. As funding permits, I will invest in a proper lighting setup. It will be interesting to see how color rendering work with laser beams, they are notariously difficult to film with good color reproduction.

[@graealex]

@@LesLaboratory Yes, lasers are difficult, especially since you're often working with low-powered ones. But for all the normal camera work, not having enough light always works against you. At 60 fps, the sensor only has 1/60 of a second to collect all light. If you are underexposed, you can crank up the ISO, but that introduces more noise into the picture. Or open up the aperture, but then your depth of field gets shallow. So the best thing is to just have a lot of light to begin with (and a good lens of course, but I assume you're just using the variable stock lens). Best would also be to lock exposure, but that can be problematic if you want to be behind and in front of the camera at the same time, so having consistent lighting somewhat mitigates that.

[@pakoyones]

Hope not to be boring, but I'm wondering if the pk cap is replaced with a doorknob as the ones used in the dumper, would the performance be better or basically the same? If it is the same, I guess the 'only' advantage on using a doorknob as peaker is the compactness and robustness of that vs aluminum foil+acetate sheet DiY peaker?

[@aarongreenfield9038]

Do you have any high power argon lasers? I know they are extremely inefficient and huge, just wondering. I love the multi spectrum beam they emit. They are my favorite laser by far.

[@LesLaboratory]

No, just this small one here: kzbin.info/www/bejne/r4qsl6djZrx2j6c They show up on eBay from time to time, and I have been tempted, but power and space is an issue at the moment.

[@btno222]

Is it possible like how emf on rotational motors use, to build that mechanism on a 7inch in diameter that rotates out right of tge specialized tube where microwaves can be contained in that tubing and the emf tube is increased by also sprialling the waves out into a more concentrated focal point, umm i dunno refraction or defractions that reduces the microwaves but i feel that can be solved by emf on a higher rotation, and power, maybe even incorporate super/hyper/ sonic waving at the left to project it out? Basically trying to figure out microwave weapons that can control the microwaves without much loss and create a focal microwavable beam and smal as a quarter

[@alejandrobella6962]

I wonder, how much power has the ouput a few miliwatts ? do you need some eye protection ? I mean it is always good, but is i a must for this ?

[@GeoffryGifari]

a physics question on the dye laser: knowing that the medium is suspended in a liquid, how can we take into account the motion of the lasing particles? in room temperature there is brownian motion, and during energy absorption/light emission there could be recoil is it safe to approximate the particles as stationary as to not affect the frequency of emitted laser light?

[@LesLaboratory]

I doubt it matters, though it would be interesting to look up! If you were to assume the molecules were moving at the speed of sound, stimulated emission will be orders of magnitude faster, so much so, that it would be safe to call the speed of the dye molecule zero. Lasers exist, where the gain media is moving at supersonic velocities (chemical oxygen iodine springs to mind) and even in those, molecular motion could be considered slow to zero as far as photon interactions go.

[@chanheosican6636]

I would like to build a Nitrogen laser that Produces 165 uJ per pass. I want to make a dye laser with it. I will use 5 ma, 10 kv DC. A question how would you calculate the wavelength of the dye laser. I think you would need a Visible laser spectrometer but would the quick pulses make that difficult?

[@totoff92]

fantastic!! I was wondering if instead of of a Nitrogen laser you could use a violet pointer laser (400nm approx) as it makes most of pigments fluorescent ?

[@LesLaboratory]

Thanks! Unfortunately it is not quite that straightforward. Although a violet laser pointer will make the dye fluoresce brilliantly, it lacks the peak power necessary to threshold the dye. Dye Lasers typically require peak power densities in the order of Tens of Kilowatts, to Megawatts per square centimeter, easily achievable with a small Nitrogen Laser. It is possible to diode pump them, but it is certainly not easy and the power levels are very low (on the order of nanojoules) see this article here: link.springer.com/article/10.1007/s00340-017-6664-4 It is something I am considering pursuing, but the set up costs will likely be very high... Nitrogen lasers are cheap ;-)

[@ARCSTREAMS]

is it possible to run this with a cw laser? like a cw nitrogen laser to pump the dies and get a steady output?

[@cambridgemart2075]

Very nice Lasers, would like to see these in person, have you ever brought them to a LEM?

[@LesLaboratory]

Thanks, they are real performers. I have never been to an LEM, where are they hosted?

[@cambridgemart2075]

@@LesLaboratory They are held in Surfleet, Licolnshire. If you're on FB, look up UK Laser & Electronics Enthusiasts Group - Surfleet UKLEM. Hopefully, when things get back to something closer to normal, there will be 2 events next year

[@LesLaboratory]

@@cambridgemart2075 cool, I will keep my eye out. Perhaps the Apocalypse will be over by 2021z

[@cambridgemart2075]

@@LesLaboratory Let's hope so!

[@ocayaro]

I wasn't convinced until it decided to take a smoke

[@luisledesma586]

awesome, well presented too, thanks. Q: any other gas that would work?

[@LesLaboratory]

Thanks! Yes, probably! I suspect a CO2 laser mix would work, but you would need appropriate resonator mirrors. Argon 'might' if you made the channel long enough.

[@mastershooter64]

@@LesLaboratory are CO lasers better for higher powered lasers?

[@LesLaboratory]

@@mastershooter64 it depends in what context. For engraving and cutting, a good diode laser will give a CO2 laser a run for it's money, depending on material. There is an upcoming video on exactly this topic in the works right now!

[@Zenodilodon]

On the charge transfer type, doe the rail without the film cap connect to ground? Despite the words of " It's not going to exactly make a laser pointer " that's what I am attempting to do. I have tried making several small N2 laser heads this last 2 weeks. Been posting about it on my community tab. It's been kicking my backside!

[@Zenodilodon]

Found my answer in a write up that you inspired!

[@LesLaboratory]

Sorry I missed this comment! Yes, it connect to ground (but you found that ;-) ) Well, I mean, if you were super determined, and wanted to have a go at making a rolled capacitor....

[@Zenodilodon]

@@LesLaboratory I am super determined that's for sure!

[@michaelmitchell8218]

Deal with lasers alot and own many lasers and very powerful co2 and yag ones. I never been into these tea lasers. Always thought I should make one but never have. Just find they have not much use to them and seem outdated in a way. I’m sure they are fun to make but I think to make a good one you need to spend the money and time on quality parts.

[@LesLaboratory]

Cool! Depends what you want one for. I always wanted a tunable Laser and a TEA Laser pump seemed to be the way to go. See this video here: kzbin.info/www/bejne/Y5_ckGCPZrKjiLs These home made N2 Lasers exceed the specifications of commercial units of a comparable size. The latest iteration produces 0.5 Megawatt Peak power with an average power of over 10 Milliwatts. You can see the measurements here: kzbin.info/www/bejne/kIKtoH17p5iIiZo

[@michaelmitchell8218]

@@LesLaboratory sorry not putting it down I know it takes some work it get it spot on, it just one of them lasers that’s hard to do something with. I know they can be powerful, I seen them in the work place cutting, etc, but they are big ones and I mean big. I know people use them of the interest of its wavelength and dye as you show in your video. But must say I think your video is one of the best for show this laser in more detail. Also wonder if you could improve them more and take it to a better level ?

[@LesLaboratory]

​@@michaelmitchell8218 No offence taken! and thanks! Yeah, I want to up the game a bit. My goal is to try and squeeze a lot more power out of it, I know it can be done, but it starts to get real tricky. Channel length can't be reasonably extended beyond 30cm or so when running at atmospheric pressure, but there are tricks like Like having two or more channels in series (MOPA configuration) or Marx Bank switching. Beyond that we end up in voodoo transmission line territory with coaxial feeds and water capacitors.

[@tachionx2]

how can you change the repetition rate? I though that the repetition rate was given by the charge and discharge time constant of the RC circuit but probably not. Thanks for the explanation and info ...

[@LesLaboratory]

The repetition rate is governed by the charge on the Dumping capacitor, the breakdown voltage of the gap, and the current supplied by the PSU in this case (So RC). Just crank up the supply to increase the repetition rate. A far better arrangement would be to make a triggered gap, so there is real control. The upper limit is ultimately determined by the temperature in the channel. Whilst it can be driven to 100hz easily in its current form, The output rapidly drops off above 40Hz, as warm Nitrogen does not Lase well. If you wanted a truly spectacular output, you run chilled Nitrogen down the Channel at a high flow rate. According to the literature, Nitrogen Lasers have been built with repetition rates above 1kHz.

[@omsingharjit]

So it doesn't need to be Q switch since it's already in Pulses form ! ! right !! ??

[@LesLaboratory]

It is already pulsed and probably under 1 nanosecond.

[@Kepler_2258]

i wonder if you could somehow get a faster pulse rate without killing the output power, would be cool to have a Constant output N2 laser, but those pulses are what excites the N2, i do wonder if you could get it to trigger like 30 times a sec though

[@LesLaboratory]

I can get a good 60Hz out of the smaller version of this Laser, but yes, you are right, if you cool the gas, you can increase the repetition rate. Back in the 1970's Nitrogen Lasers were built in Labs that could fire at kHz rates with cooled N2.

[@Kepler_2258]

@@LesLaboratory on wow that’s interesting, would be cool to build one, but I lack materials to build a nice one lol

[@georgegreen3672]

How large the high voltage ceramic capacitor and cement resistor are? I have a 15KV/1mA voltage source, is it enough? Today my first try on Blumlein line is faild, too many sparks without lasing.

[@LesLaboratory]

Between them the capacitors are 2497pF @ 30kV (so about 620pF each). They also must be doorknob types (low inductance). The resistor is 5W at 120k. You should watch the video here: kzbin.info/www/bejne/d6qxYqKVaL2Uitk. 15Kv is not enough. The laser fires about about 17kV plus. You should build a supply capable of outputting 20kV or more. Mine will run up to 30kV.

[@poodook]

Great video! Quick question - what is the effect of the feedback mirrors on the dye laser pulse energy? Should one include feedback mirrors to fully optimize the pulse energy?

[@LesLaboratory]

Using feedback mirrors will significantly improve beam quality, stability and pulse energy. some feedback is a requirement for tunable Dye Lasers (check out my other videos) the required reflectance of the output mirror is fairly low from 10-50%

[@poodook]

@@LesLaboratory thanks. Don’t the surfaces of the cuvette itself also already provide some feedback? For example, the power reflection coefficient at air-glass interface is already ~ 4%

[@LesLaboratory]

@@poodook yes, they do. In my Dye laser designs, I have the cuvettes tilted such that the reflections don't interfere with the beam.

[@flomojo2u]

I'm curious-- how well would this work with argon instead of nitrogen? Couldn't really find any info on using other gases aside from CO2 or helium. Argon is just a lot more common to have on-hand if you weld things. Is there any info out there that would indicate what various gases would or would not work, and why?

[@LesLaboratory]

As far as I know, Argon will not lase in this configuration. You might be able to use Ar as a buffer gas, but it is quite a heavy Ion, however, it would make an interesting experiment. Who knows, maybe with a long enough channel, visible Ar lines could make an appearance. Apparently if you pressurize the spark gap with Argon that are supposed to perform better.

[@nicktohzyu]

what is the benefit of pressurizing the spark gap?

[@LesLaboratory]

Pressurizing the gap means you can have the electrodes closer together, this in turn means lower inductance of the spark channel, and thus much higher speed than an atmospheric pressure gap.

[@niveknitrof5196]

Les, I’m new to this laser game, and I was wondering why the “secondary” beam from the cuvett (?sp.) comes out at a completely different angle from the incident beam? Light amplification due to reflection off the inside of the cuvett? I’m at a loss! If you have link explaining, or if it’s quick an easy to explain, I would appreciate it, BTW: You did a great job explaining you lasers! Thank you! Kevin

[@LesLaboratory]

Hi Nivek, when the beam from the Nitrogen Laser hits the side of the cuvette, the penetration depth is very Shallow, so there is not enough gain in the same axis of the pump beam to Lase. The profile of the Nitrogen laser beam on the cuvette is a short line, maybe a few millimeters in length, and in this case, there is enough gain length for it to Lase. Also yes, you are correct, reflections from the edges of the cuvette (about4%) are enough to amplify that light as well. You can Lase cuvettes pf Dye 'on axis' if you dilute the solution enough and pump it hard enough, however then it becomes difficult to do interesting things like tuning it. There is a diagram of a Nitrogen pumped dye laser setup here: technology.niagarac.on.ca/people/mcsele/lasers/LasersDye.htm

[@zachsimmons6209]

@@LesLaboratory I had sort of the same question/was wondering why the 2nd output was perpendicular. Is the cuvette glass or plastic? I would think the quality and shape of the cuvette would impact how well the pumped color works.

[@kaisersose5549]

I think the size could be further reduced, but I'd have to know what the effect of scaling this device is. For example, how much less voltage is needed when substituting razor blades for the hexagonal aluminum rod? Potentially, a feedback oscillator driving the spark gap could be used to step up a low voltage power supply. The feedback oscillator could be substituted for a simple oscillator used to drive a transformer with a few more components. At that point commonly available capacitors could be used to avoid the issues caused by the homemade version. Of course this greatly reduces the output, but given the insanely high wattage of the typical TEA laser, it may be worth a try. EDIT: The size I'm envisioning is comparable to an old Nokia "candy bar" type of phone, including the powder supply.

[@LesLaboratory]

Sure, I suppose it could be made much smaller. I do not think a razor-blade channel would be quite as helpful as you think. Whilst such a channel would lower the voltage, it would also lower the available electron energy I imagine. I have previously used sharp channel electrodes, and found them to be very poor in this application. It could be shrunk to the size you describe. I think a channel of ~3cm is practical. After that, it is just a case of shrinking the rest of the package. Small HV PSU's are readily available, I just wouldn't expect a huge repetition rate.

[@kaisersose5549]

@@LesLaboratory Thanks for the information on practical scalability. Your response was much more in depth than I expected. I didn't expect razor blades to produce anything useful, I was just hoping to get a relative figure in order to get me in the ballpark when I build the power supply. I don't have a whole lot of space for projects, so the smaller the better. Like you, I'm opposed to building something that's so structurally unstable as the typical TEA laser. Better to spend some extra time in the design phase & not have to readjust everything each time the laser is moved. I'll happily accept a vastly lower rate of repetition in exchange for increased durability & the ability to use off the shelf components.

[@LesLaboratory]

@@kaisersose5549 Totally. These builds are great in terms of stability. They don't scale up too well either. I have built one with a 30cm channel, but for TEA designs, that is more or less the upper limit. Scaling down is something I should look in to. 6cm is cute, but it would be cool to get it down to 2cm, and still be able to do useful work, i.e. pump a dye laser. I am also looking at trying to replace the doorknob caps with something more obtainable as well. I have tried removing epoxy from wire ended HV caps, but always manage to damage the dielectric and it is a lot of work, so I am looking into a design comprising of bog standard wire ended HV caps. I reckon with a bit of thought and care, it can still be made to work!

[@SimonSozzi7258]

🤯 wow! How come the lasers come out at 90 degrees as opposed to straight through?

[@LesLaboratory]

The Nitrogen Laser is focussed as a line on the Dye cell, and the gain occurs along the line. The penetration depth is very shallow so there is not enough gain in that direction to Lase, hence the 90 degree output.

[@omsingharjit]

I think no one did this - "tea laser with smoke 😄😃

[@StarBeamSocial]

What would the peak power of the dye laser output be relative to the pumped laser input?

[@LesLaboratory]

The theoretical limit depends on the quantum efficiency of the dye, and optical cavity configuration. In the literature, this is about 30% for Rhodamine 6G. For simple Dye lasers like mine, more like 10%.

[@icebluscorpion]

Wouldn't it be easier to ditch both circuits and drive the lasing spark gap with a TIG Welder in such a way to distribute the high current across multiple lasing gaps and collecting all radiation with sustainable mirrors/prisms ?

[@omsingharjit]

Why dye Laser beam is perpendicular to the Tea laser beam ! Photon Should be aline in same axis as i have learned in text book ? Can you explain ?

[@LesLaboratory]

There is a demo and an explanation here: kzbin.info/www/bejne/r3qUYpZnjZWpf7s

[@omsingharjit]

@@LesLaboratory but ... There's no explanation on why it's perpetual to the main beam

[@magx1]

What did you use for a HR and most importantly, for an OC? I tried using a homemade resonator, but could only get superradiantly lasing. I was unable to obtain oscillation. I'm certain the mirrors are very well aligned. My only doubts are over the correct percent transmission (which should be high, given the extraordinary gain), which shouldn't be critical at all.

[@LesLaboratory]

The HR was a plano UV coated aluminised mirror. If I had the money I would have used a radiused mirror, to compensate for the divergence of the reflected beam. There is no OC in this design, but the literature suggests between 4 and 10% for optimal efficiency. As you say the gain is massive anyway. Using a HR will more then double the output at one end.

[@TheLightningStalker]

@@LesLaboratory Where did you find such a tiny mirror? The commonly available ones are all one inch dia.

[@LesLaboratory]

@@TheLightningStalker I got the mirror from Thorlabs. They do miniature UV enhanced mirrors.

[@TheLightningStalker]

@@LesLaboratory Very helpful thanks

[@dombaines]

I love the suggestions and it brings back lots of memories but watching these raised a few concerns. I used these and other types of laser right up to class IV in PhD for fluroescence spectrosopy. Please please mention safety goggles etc as there are lots of hidden dangers here, these are on an open bench, your lasers are not secured and I see no interlocks etc. They operate at UV 337nm and the peak power can do some serious damage to anyone not just the operator so you need googles to protect the eyes. Even the dye cell output I would expect is in the same category. Reflecting either off a surface into the plane of the eye so it can be seen, it doesn't bear thinking about what might happen! A split-second direct exposure to such a 200 mW laser emitting even if it were 100 metres away can cause permanent eye damage. Pulsed UV radiation from nitrogen lasers is definitely capable of causing eye damage before you even mention the dye cell output frequency shift. The laser pulse or beam may damage the eye before the eys will have even reacted that is the danger of these. Of course noone thinks it will happen to them, but it can and the damage is often permanent. The high voltages are an issue too they can kill.

[@LesLaboratory]

Thanks. In later iterations, the Dye Laser is Mounted on on optical breadboard, where all beams are terminated. Goggles have been mentioned in the comments and since there is a lot of Laser craziness on KZbin, I had already suggested that this will be addressed in due course. The classification of this Laser would be 3B. Although peak power (in watts is high) pulse energy is on the order of micro-joules and average power is sub 20mW. At this wavelength, UV would never penetrate the cornea, that said, a corneal ulcer is exceedingly unpleasant, and eye protection should be worn. The Dye Laser on the other hand could damage ones retina if you chose to stare down the beam. All Laser beams diverge to some degree. At 100m distance for a 200mW Laser as you suggest, with a reasonable 0.5mRad Beam divergence, would yield a spot size of over 50mm, giving an irradiance 0.097mW per square mm at the target. Assuming a person had dark adapted eyes, for a pupil diameter of 7mm, this would equate to approximately 3.7mW of Laser light entering the eye. A moderate hazard, but hazard nonetheless. The High voltage supply, whilst it deserves respect, is quite low current. It would give a nasty shock, which could lead to an accident, but is highly unlikely to kill. This is in stark contrast to the danger posed from a Flash-lamp Pumped YAG power supply, which are positively lethal.

[@dombaines]

@@LesLaboratory OK I was dealing with class IV Nd:YAG with primary a 1064nm and the more familiar green 532nm both were high power. The pumped dyes were 400nm up to 980nm so seems like lots of similarity.T This was 17 years ago now.

[@LesLaboratory]

@@dombaines I have a great respect for Nd:YAG, and have built several. One is doubled to 532nm, and pumps an unusual solid sate dye Laser. In any case, point taken, so thanks for reminding me about safety! It is something that is not adequately covered on KZbin, especially how to purchase the correct eye protection for the job, so I will delve into correct wavelength and Optical Density selection for Lasers. Cheers! Les

[@magx1]

I have built both TEA and TERP (Transverse Electrode at Reduced Pressure) nitrogen lasers. According to my sources, charge transfer circuits are a little less efficient than LC inversion circuits for N2 lasers (although they might be ideal for CO2 lasers). However, I think charge transfer circuits offer some advantages for DIY-ers. First of all, charge transfer circuits work better with low current power supplies. I think the net voltage (across capacitors and laser electrodes) is greater when a charge transfer circuit is charged with a low current power supply. I suspect this is due to greater charge leakage that occurs with LC inversion circuits, but I don't know this to be the case (any thoughts?). All I know for certain is that I seem to be able to get a wider laser electrode spacing and/or higher frequency of pulses, using a CT (Charge Transfer) circuit as opposed to an LCI (LC-Inversion) circuit. The big difference I'm talking about occurs when using an extremely low current power supply, such as a Wimshurst Machine or similar electrostatic device.

[@magx1]

The second thing is simplicity. With CT circuits, no inductor or charging resistor is required. With higher voltage via wider spark gap spacing however, placing a resistor (or inductor) around the laser electrode channel prevents flashovers (sparks that track across the dielectric surface and bypass the spark gap). Although this eliminates flashovers, it might also result in reduced laser output.

[@magx1]

Finally, the issue of inductance is different. With the LCI, both capacitors (on opposing sides of the electrode channel) must have extremely low inductance for the laser to work. This obviously means both capacitors must use parallel plates (like aluminum foils) charged with the same polarity, seperated from a common oppositely charged plate through an extremely thin dielectric (obviously you know this, but I'm merely providing it in an attempt to be more comprehensive). With a CT circuit however, only the peaker must be designed with such a great emphasis on minimizing inductance. The dumper is much more forgiving in my experience. This means larger capacitors might work as dumpers (though more energy might also be wasted). I've successfully used Leyden Jars as dumpers. Wire connections between dumpers and peakers, opposite the sides with the spark gaps, might even work (I was able to make it work, if I remember correctly). It's not that minimizing the inductance of the dumper isn't important, but it just seems less important than it is for the peaker. Given this apparent fact (please correct me if I'm wrong), I think the CT circuit offers a greater range of experimental potential for DIY nitrogen laser designs.

[@magx1]

My apologies for the series of replies - every time I tried to post it in total, the result was truncated.

[@LesLaboratory]

@@magx1 Ha! Yep I don't suppose KZbin comments support large replies! Sure charge leakage is an issue with LC Inversion circuits, but it depends on the capacitors. Back in the day, I built a low pressure N2 Laser using Doorknob Caps rather than PCB caps as shown in Sci-Am and it worked gloriously! PCB (or aluminium foil with dielectric) are pretty leaky. You can see the corona glow in the dark around the edges, and it is bound to drag down a low current supply. For sure, regarding your comments about the inductance of the Dumper, the discharge from the Dumper will contribute to Lasing if the inductance is low (there are academic paper to back up this assertion) , but it is the Peaker that is critical in terms of inductance as you say. Given how well this design works, I am convinced that many cheap small value wire ended caps (like with MMC's for Tesla coils) could be pressed into service as a Dumper cap, significantly reducing the overall cost of the design. I will have to order some and give it a go...

[@patchvonbraun]

Have you used this to pump fluorescent dyed acrylic? Did that with my N2 laser a few decades back../

[@LesLaboratory]

Not yet, though I do have a solid state dye laser (the medium is Rhodamine in Plexiglas). It would be kinda cool though :-)

[@patchvonbraun]

@@LesLaboratory I used plastic triangles such as you might find in a geometry set back in the day. They were often available in fluorescent colors.

[@MilanKarakas]

Long time ago I built weird nitrogen laser with copy of the diagram from PRA-LN100 laser (TEA). But, after marx bank generator consisting of only two stages (to doorknob capacitors), there is 15 m of 75 Ohm cable feeding to the laser head. No additional spark gap on the laser head. And since then I lost interest in building any laser. My bad.

[@LesLaboratory]

Cool! Do you have any more information on that?

[@magx1]

Where did you get the cuvettes? I make mine out of RTV and microscope slides. I hate fighting the leaks!

[@LesLaboratory]

Hi. I used to do that, but it is a pain. These are Hellma Cuvettes I scored on eBay at the right price, but I have also used the inexpensive Chinese ones as well, and they are pretty reasonable. The seller ID is samnacu, and they sell stoppered cuvettes for ~£30 UKP. Stoppered ones are the business, easy to handle, resistant to spillage if you are clumsy like me and they keep well in terms of evaporation. You can get square lid cuvettes as a lower price (~£20 UKP), but your solvents will evaporate quite quickly, and the lid won't stay on if you knock it over. It goes without saying, you need the cuvettes with 4 clear windows. It is possible to polish the ones with 2 ground glass slides, but once you factor in your time and materials to do it, you might as well have spent the money!

[@magx1]

@@LesLaboratory Thanks you very much. I tried searching eBay for user ID samnacu, but my search results turned up nothing.

[@LesLaboratory]

​@@magx1 www.ebay.co.uk/itm/3-5ml-10mm-Path-JGS1-Quartz-Cuvette-With-Stopper-For-Fluorescence-Spectrometer/282377501375

[@magx1]

@@LesLaboratory perfect! Thank you very much

[@billlumberg5746]

Can use this laser for a presentation...

[@LesLaboratory]

Presenting what?

[@catandtheostrich]

Do you have build instructions with parts lists posted somewhere? I'd love to replicate this work.

[@LesLaboratory]

At the moment, the only documentation are these videos. I am in the process of creating a written document though. I will post it here when it is ready!

[@fyzxman3293]

@@LesLaboratory Knowing how lasers work, but the specific tricks in how they are built -I lack. I am very interested in seeing how to build your take on the N2 laser, if you are not sure what I am saying, I am very interested in building the charge transfer version 2 design. Because I did not see how the gas feed worked and how the charge-transfer circuit works, I am very intrigued and trying to curb my anticipation. :-) Being familiar with the first circuit design and laser TEA based on the Scientific American article. This is interesting. DO the electrodes connect to the capacitor plates on top? What electrical current source are you using? Thank you for the video. Please provide some documentation for building and understanding the circuit at least.

[@omsingharjit]

How can we make tea laser continuous in vaccume condition ?

[@LesLaboratory]

You can't. The Laser self terminates, and so can only be run pulsed. That said, you can get very high repetition rates under the right conditions.

[@omsingharjit]

@@LesLaboratory can we get khz range of pulses !!??

[@LesLaboratory]

@@omsingharjit Yes, according to the literature, this it is possible to get several kHz output with proper design.

[@caryweaver7045]

23:48 That is just so fucking cool. How dangerous is it to view a TEA laser like this with the naked eye? Very High peak power but very low average power.

[@LesLaboratory]

Thanks! As with all Lasers viewing the beam is hazardous. I broke a webcam once that caught a specular reflection from a dye Laser like this.

[@Kilroy01]

You talked about scaling the laser down, but what about scaling the design up? I am wanting to build a single pulse setup that it capable of ionizing a channel of air.

[@LesLaboratory]

in this video: kzbin.info/www/bejne/kIKtoH17p5iIiZo I demo a 30cm long TEA nitrogen laser that outputs half a megawatt. TEA lasers don't scale very well though. for higher powers you would need a low pressure design. To ionize air channels, I'm pretty sure you need well over a Megawatt. I believe it has been done with excimers. Is the intent to get it to conduct high voltage?

[@Kilroy01]

@@LesLaboratory I am interested in the possibility of using a nitrogen laser to direct the output from a large Tesla Coil. I have a very large HV cap. I just didn't know if it would be suited for this purpose. The cap definitely has the energy capacity. 83,520 Joules. (No that isn't a typo. It's rated 24KVDC @ 303.8 Mfd. It weighs 400lbs).

[@LesLaboratory]

@@Kilroy01 Now that is a capacitor! Unfortunately, its not about how much power you have available, but how fast you can dump it into the channel. This has to be done on the order of nanoseconds, which necessitates low inductance, low capacitance values. You could build a Large Q-Switched Nd:YAG with it, and triple the output with non-linear crystals...

[@johngreen4610]

do you have any figures for output pulse length and millijoules per pulse?

[@LesLaboratory]

Yep! Everything you want to know about measuring these and the output powers is here: kzbin.info/www/bejne/kIKtoH17p5iIiZo

[@johngreen4610]

@@LesLaboratory Thanx.

[@ernstboyd8745]

A SOUND ABSORBING BOX AROUND THE LASER WOULD STOP JITTER IN OTHER EQUIPMENT USING THE BEAM

[@LesLaboratory]

It might well reduce noise in the sensor. They are microphonic, and so will pick up loud enough noises.

[@DaveEtchells]

I’m coming very late to this, but with CO2 in the gap, it’d lase at ~~10um. At 300-500 kW per pulse, would it be able to ablate material to engrave it, or is the total amount of energy per pulse just too low? How about if you just used a boatload of doorknob caps? (With a different choice of gas/wavelength, could it ablate metal?)

[@LesLaboratory]

Possibly. I havev actually ordered CO2 laser cavity optics to try this...

[@DaveEtchells]

@@LesLaboratory I can’t wait to see the results, that’s something I’d be interested in trying myself! (After you’ve figured out all the hard parts 😉😂)

[@monkeybase01]

Hello, your videos are very interesting, but I'm a total laser noob, so I have a few questions. Why doesn't the paper burn when you laser upon it? What is the purpose of your kind of laser? Can you cut with it?

[@LesLaboratory]

Thanks! Although the peak power is very high, the average power is in the milliwatt range, so you can not burn or cut with it. Laser like this are used commercially to do things like analysis, for example Fluorescence Spectroscopy. I build things like this because they are a technical challenge. There is something special about being able to build a Laser from scratch, rather than just buying a laser module. Besides, with a Dye Laser I can generate any color I like!

[@monkeybase01]

@@LesLaboratory Very impressive :)

[@thorjohnson5237]

The other thing you can do with it (since most things reflect UV)... is use it as a LIDAR for things like clouds and such.

[@ARCSTREAMS]

ok i can wrap my mind around the emission from the tea laser coming out from both ends of the device because of the discharge region having a shape even without mirrors but i assume the light is still spreading out and diverging or at least a small portion of it that is not in the direction of the cavity right? but what i cant figure is how come there seems to be a creation of a beam with directionality from the dye cuvette without mirrors? should it not be emitting photons in all directions? or does the reflection from the glass act like a feedback? also why were there no beams visible from those that were hitting the paper in the back at 23:00?

[@LesLaboratory]

Ok, so question 1: Yes, light would be emitted in all directions in the nitrogen, however most of the gain occurs longitudinally. Little to no gain would occur across the small section of the channel. Question 2: So a couple of things happen here, as you point out the walls of the Cuvette will reflect back about 4% of the beam back into the cell, providing some feedback. Also as the cell is at an angle, the focused beam is not a spot, but short line. The gain predominantly occurs along this line. This can be proven by tilting the cuvette, so that feedback from the walls can no longer contribute to Lasing. As with Nitrogen Lasers, Dye laser have exceedingly high gain. With a proper cavity they produce really quite reasonable beams, and with a diffraction grating instead of a full mirror, youu can tune them to any wavelength. See here: kzbin.info/www/bejne/Y5_ckGCPZrKjiLs Question 3: You don't see the beam going back towards the paper because of the way the beams scatter through smoke. If you have a Laser pointer you can observe this yourself, If you point the beam away from you in fog or smoke, the beam will appear much dimmer then is the beam was coming towards you.Light tends to scatter forwards off of smoke particles.

[@ARCSTREAMS]

@@LesLaboratory im so happy you are giving me replies by the number as it's easier to follow and that is how i usually ask q's,, ok so 1)by gain you mean stimulated emission in one direction right? but again there must be uv photons coming out each end diverged like a flash light flood only they might not be so visible as much as the central axiz which has many photons in parallel correct? 2)ok so im right and the glass contributes to feedback and creating the beam shape right? also i assume the dye must have a longer exited state life than the tea laser so that feedback and stimulation occurs right? environment

[@ARCSTREAMS]

@@LesLaboratory for some reason my last reply seems to have been cut short by yt script messing me up again,, but let me continue where i left off 3)you are right about the beam being less visible going away but i figured it should still have been somewhat visible since the other beams were so bright,maybe there brightness dimed them including the brightness from the spots on the paper ,i guess they scatter away like that having something to do with the nature of the photon ,interesting if it has a directional property of scattering forward btw i have a suggestion that is easier and cheaper for you to fog up the room ,do what i do and start using glycerine, a few millilitres of it heated on your stove top with a circulating fan does the job nice and it lasts longer ,i used to smoke alot on purpose to be able to see the beam when i do my project lol but thankful i figured this easier way out ,even the dimmest of light is nice and visible this way, btw id like to ask you many q's i have regarding my project as im trying to create a collimated beam from white light off an led

[@ARCSTREAMS]

@@LesLaboratory i had to come back on this,, are you saying the incident pump beam going to the rhodamine beeker is simply going through the solution and the lasing is happening in that region of the beam through the solution and then as it exists out at a different angle without any feedback it is coming out as a beam of different color or frequency on its own juts like through a ktp crystal for example? but how come the tea beam was hitting the other beeker dead on and it was lasing perpendicular to this beam on both ends? how does that make sense? how did it pick this direction without feedback?

[@anilsharma-ev2my]

How many laser power cook the food ??boiling the water ???

[@LesLaboratory]

This is a complex question. Depends o the mass of what you want to heat, the wavelength of the Laser and so on. I cant imagine it would be remotely efficient. Food would likely undergo ablation and photolysis which would have unpleasant results.

[@anilsharma-ev2my]

@@LesLaboratory use laser light Institute of microwave Magnetron

[@aarongreenfield9038]

What is the output power?

[@LesLaboratory]

Average power is probably a good few milliwatts (depends on the repetition rate). Peak power is probablly well over 300kW as it can drive dyes to super-radiance easily. I have just ordered some Laser energy detectors for measuring high energy pulses (not the same as regular CW power meters) Once these arrive, I will be doing a video where each of the Nitrogen Lasers is accurately measured. Stay tuned!

[@anthonyrickardii6198]

Can a variable transformer be used to power the laser. Probably a dumb one just thought I asked

[@LesLaboratory]

You need a decent DC high voltage supply. There is one described here: kzbin.info/www/bejne/fZO0dpSkacyqja8 These lasers do not require the vast amounts of current provided by mains transformers, plus, accidents with mains HV stuff can kill. ZVS drivers are the way to go small and efficient.

[@georgegreen3672]

what pressure of the nitrogen? can it work under gas pressure larger than 1atm?

[@LesLaboratory]

The channel itself is open to atmosphere, nitrogen is at a flow rate that is just enough to displace air, so atmospheric pressure. The spark gap is pressurised to 2 bars. You can run at higher pressures I believe, but as you increase pressure, so too does the speed of the discharge.

[@georgegreen3672]

@@LesLaboratory what is the meaning of "the spark gap is pressurised to 2 bars".

[@georgegreen3672]

@@LesLaboratory if using two Neodymium magnets to form the channel (N-N or S-S or N-S), what will happen?

[@georgegreen3672]

@@LesLaboratory thank you, I like your work very much.

[@LesLaboratory]

@@georgegreen3672 the spark gap that transfers power to the peaking gap, is pressurised. Pressurised gaps are high speed, low inductance switches. Regarding magnets, no idea. I have not tried it, or seen reference to it in the available Nitrogen Laser literature.

[@ProVampFire]

Why not just fill the spark gap with nitrogen, Plug it and call it a day? Is there a need for a constant new nitrogen supply?

[@LesLaboratory]

There is a need for fresh N2 in the laser channel, but sure, you could pressurize the gap and seal it. I considered adding a Schrader valve, but never got round to it.

[@ARCSTREAMS]

did you put the dye between a fabry perrot resonator?

[@LesLaboratory]

Yes, a flat-flat Fabry Perot. The output coupler is 30% R 70%T and the high reflector is a plane aluminium mirror.

[@ARCSTREAMS]

@@LesLaboratory 1)and i guess this helps boost stimulation and output power ect despite the dye already having pretty good gain but obviously not as much as the pump laser? 2)tell me these mirrors for lasers are they usually only silvered to certain amount in order for them to be totally or partially reflective? and do they work for the majority of the visible spectrum band? or do they sometimes use materials other than silver? just wondering if silver can work for most because i seen some ppl make homemade lasers using normal house mirrors they cut 3)can the mirrors also work the same no matter the orientation? 4) wow i assume you used 30r and 70t because the dye is already giving such good gain and all it needs is a 30% boost in reflection and allowed to output 70% out? that is awesome compared to the usual 2% out 5) the full reflector is a second surface house mirror?

[@ARCSTREAMS]

@@LesLaboratory did you have a focusing lens after the output coupler?

[@LesLaboratory]

@@ARCSTREAMS yes, a 40mm FL lens, though I have since replaced it with a longer focal length for tighter far-field spot size. Any lens of between 40mm FL and 80mm FL will be fine. I get my lenses from old cameras, scanners, and laser printers. They can be pretty pricey otherwise.

[@ARCSTREAMS]

@@LesLaboratory the blue beam did not appear to be tightly focused when being incident on the glass cuvette? and why was part of it being reflected? also i thought you need to have a hair line elongated focus to get a good region (energy /volume) to get a lasing in the form of a cylindrical beam ,how did you manage to get it from a single spot specially without further collimation or optics to shape the beam ?? the orange beam width appears to be much bigger than any focused spot ,not sure what is happening here? yes i get most of my lenses the same way from old cams including from an old pair of binoculars and prisms included ,costly items if sought elsewhere could you please awnser the above comment where i asked you 5 questions?

[@ARCSTREAMS]

cant you simply run this thing cw using a high frequency fly back transformer? why must there be a capacitance discharge and the design be so complicated with the foil and resistor etc? i built a cylindrical capacitor using glass tube and aluminium foil and used it with the output on my fbt to create nice bright long arcs or sparks of a few inches long, why cant i simply hook both end to a couple of copper plates i have and get the same results?

[@LesLaboratory]

Unfortunately no. Nitrogen lasers self terminate, so they can only be run in a pulsed regime. The capacitors must be exceedingly fast to populate the upper laser level, which only lasts about a nanosecond at atmospheric pressure. It is possible (in the literature) with fast flowing gas to drive them at repetition rates approaching 1kHz.

[@ARCSTREAMS]

@@LesLaboratory first thank you for replying and fast, now i have several q's, 1)what do you mean by self terminate? can you provide a more specific explanation of what is happening at the quantum state to the nitrogen atom and what self termination implies? 2)is this like a ruby laser that also has to be pulsed for it to work and it cant be continuous? but i thought electric arcs or sparks have a repetition rate of there own and there own frequency no? i never understood why ruby laser cant be pumped by uv light continuously or what all this means 3)you drove it at fast rep rate enough to look like a steady beam though so i have trouble understanding what is meant by pulsed or continuous with respect to an electric field or light pumped or other means 4)if 60hz is considered cw then 1khz is even better no? again im not sure what cw really means

[@ced3763]

can we mix die ?

[@LesLaboratory]

It is possible, but you have to make sure the emission and absorption curves don't overlap, or they steal energy from each other and refuse to Lase.

[@ced3763]

@@LesLaboratory good point !

[@btno222]

Why is it pulsating

[@LesLaboratory]

It is a pulsed laser, and cannot be driver CW.

[@Scrogan]

Now Q switch it

[@parsonsfra]

Do you need safety glasses for this?

[@LesLaboratory]

Yes, it is tens of milliwatts average power with peak power for the Nitrogen laser pump being hundreds of kilowatts.

[@parsonsfra]

@@LesLaboratory Thanks for the response. I figured you would need goggles. I've heard elsewhere that you can sometimes get away without eyewear for some pulsed lasers (I would assume this only applies for diffuse reflections). I personally wouldn't test my luck, though.

[@martijn4740]

wel no mirrors is not a 100% true the internal reflection in the tube is acting like a mirror

[@LesLaboratory]

You are right, reflection off the cuvette walls is in the region of 4% which will give some feedback for sure. However at these powers, you can tilt the dye cell, thereby eliminating the feedback, and they will still Lase. The internal gain is that high.

[@martijn4740]

@@LesLaboratory awesome video need to get my hands on a small yag or ruby laser

[@TiagoTiagoT]

@@LesLaboratory What if the dye is inside a cylindrical container?

[@qewqeqeqwew3977]

"High performance" XD

[@LesLaboratory]

In the scheme of things 100 pulses per second at 300 odd kilowatts peak is very respectable as Nitrogen Lasers go. They are very inefficient devices, however they are exceedingly useful!

[@qewqeqeqwew3977]

@@LesLaboratory IMHO, high performance and high power are different things. For example, a 5W Chinese laser diode for 20 USD is high power but absolutely useless for any serious application. What about repeatability, thermal stability, temporal and spatial pulse shape, coherence etc. What is the pulse duration, when you mention peak power? Anyway, I'm just annoyed by the amount of clickbait titles on YT, don't take it personally.

[@hassansheik4171]

Tv BBC puts wiki

[@LesLaboratory]

I'm not sure what you mean, can you clarify?