EEVblog 1412 - Argon Ion Laser TEARDOWN! 

It's a water heater (25kW) with coherent power on indicator (10W).

For the first time: Don't take it apart, Turn it on!

Donate it to Photonicinduction to derive maximum tolerance values 😄

and 30 years ago, we carried several of them, around the world... For stage shows and performances... 20W was small, we had up to 100W. The water cooling was the nasty bit, since it had to run at all times, every day in different venue - different fittings, drains and distances. Plus I do remember having had huge transformers, beside the main PSU, huge = 200kg++.

Dave 2021: It's shiny, shiny equals expensive.

The thing you thought was the powermeter is actually a selenoid. Larger argon tubes have a built in refill reservoir since some of the gases get embedded into the tube so the pressure drops over time. The attached tube is pinched off on one and and contains some gas that can be added by sequentally opening the two valves, every time giving a small pulse of gas until the reservoir is depleted and the tube needs a complete refill.

Hey Dave, nice taredown. I believe we used to pull the six strongest lines out of this one, but because it doesn't have krypton there are no red/orange lines. But plenty of lines in the blue green and violet range. The main beam with all the lines has a greenish cyan colour, that any ion laser user will remember. That rear mirror adjustment is super sensitive, the difference between output and no output at all from memory. I believ that the output mirror and the rear mirror are specially formulated dichroic mirrors to optimise the lines that the laser was designed to produce which is why they don't look as reflective as you would imagine. But they certainly are in the frequencies desired. Cheers Dave.

The tube thingie over the brewster window is to keep dust out. High power laser optics can be damaged by dust burning in the laser beam. This damages the glass optics/mirrors and causes them to further heat up and cause more damage by thermal runaway.

Thanks for sharing, spent many hours re-tubing Kryton (413nm) Innova laser heads in a previous job, used for CD/DVD mastering equipment as a light source. Kept the system service eeprom and service manual to repair heads/PSU, as was certified by Coherent many years ago. The device you highlighted as monitor diode is actually Ar or Kr Gas reservoir. Which will add gas as pressure deviates from ideal based on tube voltage. Noble gasses become trapped under sputtered Cu inside the plasma tube, which lowers the pressure. The AlO ceramic plasma tube has dozen's of Cu cups which have a holes where the narrow confined plasma passes thru. This sputtering eventually leads to lowering of the output power as the sputtered by products deposit on the back of the brewster windows. In our application the tubes only had a 6-8k hours life on time and cost >$20k. Fascinating technology (wasteful) to generate less than 1 W output @ 413nm!

The flexible metal tube is to seal light in and dust out and take up thermal expansion.

The AvE label makes this worth twice as much and also twice as exciting.

Dave, you just took me back to uni days with Brewsters Angle, I’d have to go back over notes and lectures I’ve still got to remember it all again! Thanks for the trip down memory lane 😊

They use Invar rods between the mirrors for stable lasing. The optical cavity length (distance between the mirrors) must be a fixed number of wavelengths at the resonant frequency, so obvs if the cavity length changes it buggers up the output.

Fun watching you try to figure out all the parts in there, it's always a good time being exposed to something new, even if it's something old. This brought back fond memories of spending hours pouring through Sam's Laser FAQ, interacting with some super smart laser physicists and technicians online and messing with and building all sorts of lasers as a hobbyist.

Take a drink every time he says "for those following along at home"

The multi-line argon lasers have gorgeous beam colours.

Sir, your channel content and information delivery is unique.. I must say, it is very pragmatic... thanks for everything you do for your followers....🙏🙏🙏 From India

I used the bigger brother of this for my masters but for the phd follow up we replaced it with a diode pumped solid state laser. much more efficient. 56kW for 32 W laser light (all lines) or 12-15 W single line. The brewster window has to be covered as this is within the laser cavity (those end at the mirrors) and thus the laser power there is much higher and it will burn in any dust quickly. And we had a service contract with coherent as the tube needed to be replaced about every two years. Once the service techincian tried to bring it back to spec by cleaning the brewster window with an acid, but then it was even worse and they had to replace it eiitherway. Nice to see it again.

You now just need the freaking shark to attach it to!

Good video. I'm one of the manufacturing engineers at Coherent for the Ion laser product line.

In the 90s I did amateur laser shows for my Brother's band. Started with a red he-ne tube, later got my hands on a blue + green argon that was only a few watts. Then had a super rare, beautiful deep purple helium-cadmium laser. This had a more complicated separate power supply unit than the Argon, and on startup a big fat tungsten filament started glowing brightly to vaporize the cadmium before it would fire the gas discharge supply. Both of these lasers were temperamental as hell, with the mirrors going out of alignment and requiring long warm up times before they really started humping. These cost well into five figures new, and the salvage guy I knew was selling them for 1500+ used with thousands of hours on the meter. Nowadays, diode lasers are available up into the UV range and lasers comparable to these gas giants are cheap as sand in comparison.

I need to find an excuse to use "polychromatic acousto-optical modulator" in conversation now.

When we see such massive things, what we expect to hear: Photonicinduction: "Let's fire it up!" EEVblog: "Let's tear it down!"

Awesome teardown, thanks for sharing!

Very amazing Laser! Thank’s for the teardown!

There's no filament at the anode end, it's just a block of tungsten embedded in copper. The I300 series have a personality module which is on that PCB in the head, it talks to the PSU to supply the stored configuration data for the individual tube. The water flows in at the cathode end and out at the anode end as that's the hottest part; that's why the thermostat is at the anode end. The filament feedback lines are fused because the filament runs at 50 to 60A, you wouldn't want a short on the feedback lines as it would cause them to glow if they weren't fused!

"if we need that extra push over the cliff, you know what we do?" "Put it up to eleven."

Very good descriptions/info, Thanks!

I can't get over the AvE / EEVBlog crossover

Those invar rods....WOW that's neat! Reminds me of the CRT days. Sony had invar shadow masks in the Trinitron CRTs. Very low thermal expansion to reduce convergence errors as a tube heated up. Then there were the NEC monitors that used aperture grilles where if you smacked the monitor on the side, you'd see convergence go nuts for a second as the wires vibrated.

Well that's a new one for me. Love the video man

I have an HeNe laser with that polarizing angled window. I’ve noticed that you get a beam that comes out almost perpendicular to the main beam. I’m guessing the metal spring is there to absorb the stray beam and dissipate the heat from that

Invar was also used for Synchronome master clock pendulums due to its excellent low expansion characteristics.

You will need the "safety squint" sign as well to operate it. Great video!!!!

Love the mix of mechanical and electronic. I actually think you could do a part 2. Cheers Dave

I love the AVE style warning label!

11!

We had some devices that looked a lot like this in the first research laser printers. A decade or so earlier, used an invar pendulum to precisely measure the local value of G, the gravitational "constant."

Holy moly I remember using those, one argon for 488 and 515nm and one for 658nm red krypton. Beams all mixed together with dicro mirrors then piped into a PCAOM. Eventually got a set of yellow green optics for the 560ish line of krypton. Yup they make great space heaters if it's chilly where you are doing the show if you use a water to air heat exchanger. Built my own using automotive radiators and the cooling fans. Because 480V 3 phase at 50A per phase and plumbed water is a horrifying combination. Early 2000s. Also the lasers cost about as much as a new car when they were new. None of mine were new though. The assembly you thought was a photodiode is the gas replenishing module. A valve that dumps the argon into the tube as it gets buried. I disconnected those as the psu would fire it too much if it thought the tube was too low on voltage or no reason at all. All that white ceramic is beryllium oxide as well. I modified these heads to run on SP 451 exciters as well. Kilowatts for miliwatts. 😂

I love the warning sticker on the side. It needs to be applied to more gear.

Love the AVE Sticker!

Teardown argon laser - thumbnail shows red beam. I started working at Spectra Physics in 1978 on lasers, good times!

Let’s do a gofundme campaign to have this sent to Ben @Applied Science. He will surely make good use of it for the benefit of us all! Thanks for the great video Dave!

We had several Coherent lasers that were purchased as scrap. We never did get them working in spite of pumping one down to vacuum again and having a 3 phase supply on hand! (One was Spectra Physics)

"If you let all the vacuumie out, THEN.... Your laser don't work so good anymore!" - EEVblog

What a timing to open YT. Giant ass Argon LAZER? SIGN ME UP!

Thought you were in the TV for a sec lol

Oh man, Dave...you gotta turn it on for us!

That laser is still more efficient than the solar roadways.

This is what I'm waiting for 😤

Thoroughly interesting enlightening entertaining stuff you are talking about that I got no idea about what you're saying. but I always like watching your videos anyway because of your joy la vivre and the little bits of stuff I do learn I suppose.

The Ave sticker is more appropriate than ever ....

what a beast! cheers Dave that springy tube thing.. looks like ya cant actually see through the "coil" it would block any light that is scattered off the output lens..ya dont get 100% pass straight through some is scattered off at right angles.. ...its extra eye protection...the o-rings probably go through to the middle ..for grip on the shaft when mounting....

Great opening scene, very funny. I'm looking forward to seeing it operating. Maybe you can bounce it off the mirror on the moon.

I'm only guessing but the flexy tube on the Brewster window provides protection from dust etc while allowing adjustment of the output mirror.

point of note: argon lasers don't have red beams. they lase with blue and green lines with 488nm (cyan) being the predominant wavelength. it's all dependent on the optics, but you'll never get red.

Coherent, were competitors of Specra-Physics, both in the Silicon Valley, California. They also made mixed-gas Argon/Krypton that outputted a 'white' output. Cool stuff.

I have a really old one that runs on 3 phase power and is water cooled. Power supply is 220 and takes a key to come on. I started to tear it down to rebuild as a laser turret but it sat for decades and bolts are really in there.

Also, on these models, if the “Laser Radiation “ light is out, the system will not start, thought of switching out mine with an LED, instead of a filament, and found that it measures the current thru the existing lamp, to verify that it is on, for a safety factor. No indicator light, no Lase!!🤗 page 6-1 Photo output sensor is that black sensor at front of Laser Mirror too with a beam splitter that you unscrewed at beginning. Bellows for keeping Dust out of optics. Also inner jacket is water cool for plasma tube, outer jacket is for the Magnet cooling. You can change output mirrors to other nm, to select light frequencies Excellent Tear down!!

16:52 I am certan that this is for decoupling the laser from the housing as a flex joint. And also looks to be dustproof since if you get a little dust on it thet absorbs light it will heat up and burn/crack the light output glass puncturing the whole tube.

Great use for the AvE sticker!

A movie scene comes to mind here. "Find out why these red lights go back and forth" - William Shatner, Airplane 2

The O-ring bellow contain some platinum catalyst to break down the Ozone generate from the plasma - also it is to keep the Brewster super clean

BTW in old IBM printing machines we have had about same size lasers. Those where those printers where paper rushes true the few machines. Laser would polarize letters onto the drums and drums would pick up toners with that charge and press it and baked it on the paper. Drums were hot to.

At my college, the physics dept. had a LASER that as far as I know was only fired up on parents day. I don't remember what class of LASER it was, but it had big warning signs that said "Warning Danger of Decapitation". It burned holes though firebricks very quickly - what fun.

Discovered the Midas touch while building the XR2206 function generator.. touching around the circuit(on safe circuit) and if it works(the pin on the peaks go away) you measure the capacitance of your finger the distance of the contacts.. so I installed a 201 cap between the frequency and amplitude pin and its gone with no distortion.. We have Muncing.. Now we also jave the Midas touch...

That thumbnail is rather cool. Would easily buy a printed lifesize one and put it on my wall beside the other nerdy superheroes.

Styro Pyro would be drooling over this laser

That's a whole new level when it comes to low efficiency, LOL! But cool and interesting laser anyway

Love the sticker. I wonder where that came from... perhaps somewhere in Canada?

Super cool!

Fun fact, the lighting console that Spinal Tap toured with (in reality) had all of its faders relabeled to go to 11. I assume they did the same for their audio gear, but I did not see any of that.

"Chargin' mah lazers, shoop da whoop"

loved the eleven clip hahaha

I love that clip of the amplifier lol

Damn that's a power hungry beast! Still very cool 😬

On my engraver Laser there is a LED that uses like 30 Watt's and outputs 7.5 Watt optical. Times have changed. Sure you can't get same wave lengths and can't do same things but still efficiency is awesome. There is also a model with two of those diodes and it has limited optical power of 12,5 Watt and uses 40 Watt. Have had to correct numbers I have checked them up.

I like your warning label. :-)

These are the companies no one knows but everyone loves

It's a older version of the Folkys Laminar Derivative Drive Induction Prohibitor. Obviously it's not the best way to do it but back then it was harder to distinguish when G prime G' would transition or spring to G double prime G".

Maybe it just keeps the dust off the aperture and in general prevents random diffractions into the surrounding case.

*EEVblog* I'll never forget the video you made from 2009 about audiophools and snake oil! By the way, how's it going in Australia with the lockdowns? ;-)

remarkably efficient heater, also emits some light for strange reasons .)

I got a small unknown Argon Laser from eBay for cheap like 15 years ago. It had 150mW 448nm for about 850W input... I don't want to sound like "audiofool" but it was beautiful compared to those 445nm diode rubbish ;) Those rubber ring spring thingies are just there to prevent dust burning on the optics I think

Dave you've got to make some stickers out of the video thumbnail!!

Best. Thumbnail. Ever.

I love the AvE sticker on it.

The photodiode is on the front. The metal bellow is a dust cover. Some of the thick wires are for the electromagnet

Loved the amp hour podcast, I recommend listening to it! Just a note/question... why make the beam in the thumbnail edited to be red when they make a more cyan color at the 488 peak or green at the 514nm peak usually? The metal tube is probably just an off the shelf metal hi-vac flex hose, but it's job in the laser is to keep the dust and moister off the optics. You don't want to fire up a laser with dirty optics. Ion lasers are awesome, I need to own more of them eventually!

Just need someone to send Dave, one of those lasers they use to hit the retroreflectors on the moon.

I would think those mirror adjustment screws are 'differential screws' - 2 screw threads in one, cancelling each other out. One screw thread has a thread width (pitch) that is just a little bit different than the other one, thus the cancellation is just a tiny bit off. And so, one rotation of the screw results in a tiny displacement. (then again, you could see quite a displacement as Dave turned one of those screws...so I'm not sure)

Dont take it apart, turn it on😂😂😎 Why the hell do all the office in the building have a gaping hole!

Gotta love Spinal Tap. Thanks for the teardown - took me back a looooong way.

Maybe Photoninductions will power it on!!

I had a 1 watt air-cooled argon in the 90's. It took over 700 watts and ran HOT.

"No Mr Bond, I expect you to die" lol

Interesting. But why didn't you tear it down completely? I was hoping to get all the cooling system goodness and a look at the plasma tube. Detail shot of the board. Inside of the main monitor diode.

spec of dust on that dither optic I think, careful with taking those apart without a filter cabinet when it gets to higher levels

I can totally see a partly stripped version of these being used as a prop in a sci-fi flick as a laser bazooka. just like your thumbnail.

Some CRTs used an Invar shadow mask to stop them from changing shape with heat. Also, those electromagnets look like they're been used for the Faraday effect, which can affect polarization of light in some materials. Ben from Applied Science has a video about it.