My old boss, an engineer of the first caliber back in the 60s or 70s was approached by some exotic whiskey company that had printed incorrect information on the INSIDE of their lables. The mistake was not noticed until after the labels were attached. He said he could erase the bad info without disturbing the labels. He happened to have a friend who owned a ruby rod. (What are the odds?) He borrowed the rod and built a laser capable of burning off the printing through the bottle and the whiskey. He was successful.
Now that's a cool story to have, and a very clever way to solve the problem. Wonder how much the rod was worth back then, certainly couldn't have been cheap.
When I was a kid, my Dad had a college class ring with a ruby in it, and I read in an encyclopedia (mid 80's at this time) about how early lasers used rubies and flash bulbs. I repeatedly asked to borrow my Dad's ring, and his camera (with a hotshoe flash) to try to create a laser. I was convinced I just needed to get the angles right to make it work. I had no clue what I was doing, or why I was failing, but God bless my Dad for indulging my interests!
i had a synthetic ruby emerald cut, i had no idea if this was the same material as the ones used in lasers but i also had a camera flash unit that was battery operated and to make the flash go off there was a small button on the back of the unit, so i would put the ruby on the face of the plastic window in front of the xenon bulb and flash and look at the ceiling to see if i was getting any red shots lol i had no idea if something was working in terms of exiting the ruby but because of its emerald cut it is difficult to bother using mirrors and was hoping maybe id get lucky with internal reflections to do the trick
The amount of variables involved and the extent of how they interact is amazing. Before I ever get into electronics I truly will have to do my homework.
Duude, you are crazy, you build the things I wanted to build when I was 13, when I read it in my family's encyclopedia, I'm 30 but that was all I had back then. Loved your setup.
I have a beautiful laser rod that's absolutely enormous - 25mm x 250mm (yep, about an inch diameter by almost a foot long) - made of Hoya Nd-doped glass. It was a spare single-pass amplifier rod from LLNL's Shiva laser array that never ended up being used, so when Shiva was decommissioned its spare parts were sold off and I was able to snatch it up. If memory serves (I did the math on this a _long_ time ago) it'd take about 7KJ of flash energy centered on 1080nm just to threshold it, and it could easily take 100KJ+ if properly set up (read: selenium-doped flowtube for better transfer, liquid coolant for less melty), which would produce an _obscenely_ powerful laser pulse. One of these days I'll build a laser around it. I'll have to either get a metric buttload of 1080nm laser diodes or have a custom flashtube made to make it work though. Oh, here's a piece of trivia that's neat to see IRL: Neodymium laser rods change color depending on the light source. In sunlight and incandescent light they're pink, but under fluorescent light they're purple.
I work with similar, but larger, Hoya glass rods. We use 12 "12inch arc length" 300 Torr xenon flash lamps to pump each rod. Might be able to help you answer some questions if you ever decide to build it
"Explosion Energy" -I learned that one the hard way. 2000uf,450V..too much for a cheap disposable camera flash-tube. Hot glass shrapnel. Oww. I've been wanting to build a ruby rod laser since the 5th grade,I'm excited to see more. Science is fun! :)
I've only read about stuff like this in books. To see someone going through the steps to actually build it is awesome. I can't imagine this laser having much use but it will still be the coolest thing around
Ben, you have got to be the most interesting/intelligent people on UA-cam. Everything from super-critical extraction to homemade lasers. Dude, that's awesome!
+Matthias Wandel: I think all cars that have a internal combustion engine have them. I have the same model as in the video but I think mine is damaged since I overheated it because I ran too much current as I was experimenting with it.
Once you figure everything out, adding a Q-Switch even if it is passive, it will make wonders. You will be able to hear ionized air when focusing the beam. It sounds like an electrical spark. You will also need a series inductance to add some milliseconds to the discharge time. Lasing takes a little bit longer than the capacitor bank takes to discharge through the tube and the needed delay depends on the lasing media. Not sure about synthetic ruby, but ND-Yag needed about a 1-mS delay and lasing occurs around 1064 nanometers wavelength when using ND-Yag. I regret selling my ND-YAG Laser rig to some guy in some university in Italia.
Laser flash lamps are sometimes doped to absorb...some of the UV, this improves efficiency since UV normally doesn't contribute to the pumping (at least for nd:yag) and also prevents UV damage to the rod (solarization). Just put some of the flash lamps you have under UV light, some of them should fluoresce blue.
I wonder if it'd be possible to frequency-double a ruby rod laser. Of course that'd put it well into the ultraviolet instead. IIRC most green lasers work by frequency-doubling an infrared one. Also I wonder if an emerald can be made to lase given the right light source.
this video was fascinating. i only just learned about lasers the other week, sort of by accident, i was learning about voltage regulators, especially lm317t, and i keep reading about using them to supply constant current to laser diodes. so i bought some, and a few 2w lo diodes off eBay, with hosts, and some goggles. wow. after a few false starts i had a laser! popping balloons, lighting matches-did all that. then got some red diodes and bought a green pointer, and an x-cube, and played with making a white laser beam. i loved it all. i even bought a cheap fog machine off ebay, and the ingredients to make my own superior fog juice, to use with the mirrors i've glued to little pc fans and stuck to my study wall! now i want to use my recent high voltage learning to make flash-tubes work. maybe soon ill build a laser like this!
In my Engineering career I have spent as much as $100K on a single piece of equipment but I never get to buy stuff as interesting and fun as the stuff you have here. What fun! Thanks.
One thing you won't find in the documentation about series trigger is the circuit to keep the high voltage pulse entering the power supply charging the capacitor (and every other electronic plugged in the room). Transient-voltage-suppression dodes of proper rating (or several in series) can normally crowbar the pulse at the PSU side. Just keep that in mind if you do ever go there.
I wanted to build one of those when I was 12 years old in 1980. I almost built one 4 years later, but couldn't afford the ruby. Thanks for the memories. I didn't know about uv either with xenon.
UA-cam Most viewed/replayed parts in a video ua-cam.com/video/QgN_Z4FXuOY/v-deo.html The two video's mentioned:- How To Make Ruby in a Microwave ua-cam.com/video/ybcdRQmQcHQ/v-deo.html Ruby laser design process ua-cam.com/video/VSdUQ4oNKiI/v-deo.html
Sintered Barium sulfate (NOT sulfide! that one is poisonous) is used for diffuse laser reflectors, much much better then aluminum foil. Yes. this is the same thing you drink for x-rays. pretty common substance. Barium sulfate can also be painted as a water solution on surfaces, or wet formed in a mold then dried. Of course you need 100% pure Barium sulfate, not the flavored one used for x-rays.
I'd be interested in seeing a diode-pumped version of this laser. Blu-ray diodes at 405nm are really bright and cheap these days, and it seems like they would work more efficiently than a xenon strobe.
That's exactly the kind of laser with spiral tube I used to see on cartoons when I was a child. Always wanted to build one. Someday... (until then, learning)
I love this channel because although I understand almost nothing, I am still engaged fully. You're amazing dude, I wanna have a garage like you when I get a house.
So, are you deliberately using the capacitor bank ESR and thin wires to act as pulse-forming network or have you not considered making one? They greatly help to widen the pulse and keep it above lasing threshold, this way you can dump more energy into the laser itself instead of heating the flashlamp ;-) p.s. you absolutely have to blow something up with that huge pile of capacitors (and make a video of course), I personally would suggest some cheap disposable camera flashlamp :D
For those suggesting using magnesium to charge the rod. Too much heat. Having it far enough away to deal with the heat would prevent it from lasing. The set up he has is optimal for a demo. The flashlamps that would typically be used for this would actually have their exteriors coated in a reflective substance so that they transmit more of the light where its wanted.
I understand this is old so maybe my information is not useful but I am very concerned you don't know if your laser safety glasses can block the UV. Any reputable pair of laser safety glasses will have the wavelengths written on them that they block along with the optical density for that wavelength. It is a logarithmic scale so OD1 will block 90%, OD2 99%, OD3 99.9%, etc.. Typicallly, class IV lasers will use OD6+ at the appropriate wavelength. The glasses you show, if there are no markings, are most likely "welding glasses" which are not adaquate for lasers.
Would it be possible to use that laser safety glasses together with an auto darkening welding helmet? Just to avoid any IR/UV exposure to both skin and eyes. Or it will block the entire visible spectrum?
Excellent explanation!! I am used to see reaction chambers that enclosure the light source as well as the rod.. and probably it would be best for you to do one as well. It would protect you, it would protect the rod.. the light source .. etc. If you don't want to build one.. there is a guy on ebay from Israel that sell those quite cheap (i have seen them as low as 80 USDs - and some even have the old rod inside). Not to forget that high frequency light excitation will produce heat (such as the CO2 lasers do) and that should be dissipated within the chamber itself either by water or any other cooling technique. Excellent video!! Keep on!! Regards from Portugal..
When pumping ruby the bluish region is color temp is favorable this usually matches high voltage and lower capacitance. Similarly, the YAG prefers to be pumped with lower voltage and larger capacitance for a more reddening of the pumping color--hope this tip helps somehow with capacitance choice.
+Pulkit Sharma The first batch of mirrors came from eBay. I had an automatic search for "ruby laser mirror". They were not in great condition, and had some unknowns, so I also bought a new set from Eksma Optics. I believe really high power ruby lasers generally use external mirrors, where small/medium rods can have integrated mirror coatings.
I'm not gonna lie and say I understand the science behind this - but one thing I do understand is that you are trying to take a shitload of light energy and focus it into a concentrated lazer beam blast - a frikkin death ray. SIR, YOU HAVE MY ATTENTION!!! (And my subscription)
I love to watch ruby laser construction. Can you please tell me what size each of the large silver capacitors are (volts and capacitance). Thanks so much,
i am basically sure optical pumping the ruby and dispersing them imaging would require 360 degree tranparency on the output and syncing the laser with a particle sensor with an r2d2 for forward expansion. And the lens effect to bounce back the processed image like those old binoculars
Your discharge method for the HV capacitor bank makes me nervous. If the clip lead failed, the resistor would bring the screwdriver shank to the voltage of the capacitor bank. The length of the arc you drew from the bank when you discharged it should indicate the amount of respect you should give it. If you get this wrong once it will be the last mistake you make. Having worked with HV power supplies for years the discharge device of preference is a bleeder resistor that slowly discharges the bank after power is removed. A knife switch that can directly short out the capacitor bank before touching anything is also a good idea. One HV power supply I worked on supplied 8 KV at 5 amps, for protection it had mechanical interlocks that required the mains power to be removed, the input to the power supply to be shorted, and the capacitor bank to be shorted with a knife switch. The power supply had a bleeder resistor that took two seconds to discharge the power supply to less than 10 volts. Before working on anything a "Bang stick" which was a 4 foot long insulator with a metal hook connected via a heavy stranded cable connected to ground was touched to all high voltage points. This last safety device should never be necessary but will save your life should one of the others fail.
I use a "Bang Stick" to discharge the capacitors on our Uni's 4MeV Linear Accelerator (yeah, it's small but still lethal). Long (3 ft) Rod of Ebonite (!) and a fat ribbon of earth cable connected to the brass hook on the end. Once "Banged" you leave the stick hanging as capacitors have a sneaky habit of not discharging all the way and recover just enough to give you a another one when you least expect it. Great channel this one, keep up the good work.
Exactly what I thought when I saw it. And those cheap clip leads are notorious for failing. You MUST make a better grounding/discharge system than that! And/Or use bleeder resistors to discharge the bank to a safe voltage in a reasonable time (say, less than a minute).
Can you also pump it with burning magnesium? Of course, it is less controlable, but burning magnesium releases ~600kJ per mole of which a considerable part is emitted as light.
+Curixq: It would probably work but you would need some strips of Mg ribbon all burning at the same time. Also, it burns too hot and might damage the ruby rod.
I am working on a project with a capacitor bank of similar size and am trying determine the appropriate discharge resistor size. How id you decide what value and power resistor to use? Thanks
Love that they use a car ignition coil as an ignition device for the flash tube. A fraction of that voltage would do but I guess if you want it to really go off in that brief second ...
Good day sir! I know an older vid you produced, but instead of the xeon flash lamps, what about those super bright LEDs now available ???? Huge available duty cycles, and even constant light sources. Mind you you may have to have the 'brightness' up to just below cascade, but if you could get it right to the edge, a simple brightness increase to trigger. Longer lase time ??? Just a thought
The lamp is about 50% efficient. You could get 10% or more of the heat in the foil. I would calculate the J/gm in the foil and get the heat capacity and calculate the delt T. You might damage the foil. The foil touching the glass will make a good trigger for the lamp. If there is trouble with triggering people wrap very fine wire on the tube and use that for triggering. The reflector could be hogged out of aluminum and then polish. It won't be stable over time but for a lab experiment it would work.
Thank you Ben for your fantastic videos. Love this stuff and you are particularly gifted at laying out and presenting your tech experiments. Sincerely, John from Mt View
Question. I have a Donald Duck nite lite from the 70s. It only works in some outlets. If it lites in an outlet, it then flickers if the lites are turned off. It's not a light sensitive type. It says 1/4 watt and 120 volts on it. I suspect it has something to do w/ the wiring in the house, as it doesn't stop flickering if i point a flashlight at it.
So would the effective coherence length of this laser be about 1/2 the distance between the mirrors? Could you expand that distance and increase the coherence length (at a cost of efficiency), or would you need a longer lasing medium?
Question: If the photons inside the ruby go back and forth between the opposing mirrors and are all in the same wavelength, shouldn't them cancel each other out as they race into each other again and again? Obviously they don't, but I'd like to know what happens to destructive interference inside a ruby laser. Thanks.
Each high index (ruby) to low index (air) transition must be a zero-node. That is no EM field at the mirror interface. I would need to refresh myself for the proof, but this is the physical principle that makes laser light temporally (in-time) coherent.
How come you don't have the business end of that ignition coil hooked up? you'll only get that 20kv from the center socket (the part that would go to a distributor) and only if you have a points and condenser system hooked up to it. By itself, you only have the positive and negative _power_ terminals connected, but not the high-voltage output. Maybe I'm wrong, but I would imagine you aren't getting much out of that coil. Is there another reason it's hooked up that way?
Oh, sorry - when you zoomed in I was able to see the little wire leading off the coil. My mistake. PS - all standard safety glasses (z87.1 or newer) are legally required to protect against UV light. That's why you wear safety glasses even under a welding hood.
There's another way to get a high voltage pulse. Connect a switch and a power source across the primary of your ignition coil. Put a spark gap across the secondary. Close the switch and current flows through the primary storing energy in the magnetic field. When the switch on the primary side is opened, the voltage across the spark gap rises until it arcs across the spark gap. The size of the spark gap determines the voltage on the high voltage side. The current through the primary side determines how much energy is stored and thus the length of the pulse. By using an adjustable power supply and an adjustable spark gap you can adjust the voltage and pulse duration. The switch on the primary side should only be closed briefly and released to avoid overheating the coil.
Hey I have a question about charging up capacitors. I have a studio photography flash that has a 4 capacitor bank, all capacitors are put in parallel. This flash unit plugs into the wall, but somehow it is managing to charge the caps up to around 350 volts with only a 120 volt supply. There is no transformer on the circuit board so I am confused about how it is doing it. I tried researching it, but have not found much information. There are two smaller capacitors on the board rated for a high voltage (and they are not for the trigger transformer I don't think.) any idea how it's doing it?
2:31 - there actually is one. A mirror that has elliptical cross section. Since an ellipse by its nature has two focuses, placing light source in the one focus will guarantee that all the rays converge the second focus.
I'm 43 and wanted to build one of these when I was a young lad, it looked so easy. just buy a ruby rod that's mirrored fully on one end and partially at the output end, surround with a flash lamp and a reflector and voila, laser light!!! Now I'm wiser I know its not as easy as it sounds, a lot of skills need to be learned before a DIY attempt will work. Still, I used to drool at the He/neon lasers in the Edmunds scientific catalog, they were way out of my lawn mowing allowance money, Don't know what happened to the once bright, budding future scientist to be. I'm thinking hormones distorted my thinking and I made the illogical decision that girls were more important than school. Fuck me! How stupid! Now I'm just a lowly "blue collar" electrician who even has to dig a ditch now and then! No cool laser labs or cushy office jobs for me. God, I wish I could hop in a time machine and tell myself that girls are evil and will cause never-ending useless drama, the pussy is just not worth it. Nevermind, some paradox will screw that idea up now that I think about it. But hey, I did manage to buy the first laser pointer radio shack ever sold! In 1992 it cost $89, all for a stinking low power, maybe 2mw at the most, red diode laser. It took three odd N size 1.5V alkalines cells. I thought it was the shit at the time. Confession time! I'm probably going to hear what an idiot I am but give me some slack, this was the early 90's and this laser was extremely low powered, a modern dollar store red laser pointer will make my early laser look like a wimp. Here it is, shortly after buying my $89 marvel of modern technology, A police helicopter was flying near me, running out of fun things to do with my expensive gadget I decided to see if I could see the dot against the side of the helicopter. Much to my surprise he noticed and hovered over my location and turned on his "ghetto bird" spotlight, this bright beam of light was trained on me for what felt like hours while I was cowering on the back deck of my parents house! Anyway, given the time and how rare lasers were I probably have the dubious distinction of becoming the first jackass to point one at a low flying aircraft. It scared me straight! BTW, I still have that laser and it works. The batteries actually are the second set bought in 1993, they still hold a charge!
Yeah, it's easy to know the basics, but actually putting it into practice is much harder. I can't count how many times I've tried to make a laden jar and get it to produce a spark without success.
Chriscom28 You must have grown up with Flintstones. I made Leyden jars since i was 8,and i made my fist Van de Graff generator when i was 14 or 15. Quite litteraly its a container wrapped with Al foil and a nail in the top.Fill with water and proceed to shock the shit out of you. You probably didn't charge it properly,its quite hard to mess up something that simple.
Chris Barth - I also had a book as a young lad called something like 'How To Build Your Own Ruby LASER' with loads of B&W pictures of the ruby rods and flash tube etc. I used to dream of getting the parts and being able to put them together. As it turns out, it seems like it was a project that would have been well out of the range of my meagre kids DIY skills.
you're like the kerbal space program of unadulterated science. you make cool stuff and watch it blow up or do cool stuff, either way you definitely have fun doing this...
Coincidentally I am also working on the Ruby laser at the moment. I've got much smaller rod (6mm diameter), and it seems mine has lower doping ratio (much less intense color). I am hoping to get it working on 1000J or less. Can you post a link to the mirrors you use? Their color is... unexpected :-)
if it's pumped and well synchronized, you can use additional rods as amplifiers. peak powers become very high though which tend to uncover any weaknesses in your optical elements (esp the rod, maybe why Ben's ruby had a crack on the end).
Hello, great video, I was wondering what wood was used for the lasers base (I want something that my makes my projects look a little bit more professional than plywood)
I have to say I didn't know anything about arch lamp ignition, and to think I was looking into making some arch lamp drivers, I might have been frying bulbs without this information!
![[UA] NAVI vs MOUZ | BO5 | IEM Rio 2024](http://i.ytimg.com/vi/CMBYk0cbGoA/mqdefault.jpg)
My old boss, an engineer of the first caliber back in the 60s or 70s was approached by some exotic whiskey company that had printed incorrect information on the INSIDE of their lables. The mistake was not noticed until after the labels were attached. He said he could erase the bad info without disturbing the labels. He happened to have a friend who owned a ruby rod. (What are the odds?) He borrowed the rod and built a laser capable of burning off the printing through the bottle and the whiskey. He was successful.
Now that's a cool story to have, and a very clever way to solve the problem.
Wonder how much the rod was worth back then, certainly couldn't have been cheap.
@paul beenis does anyone ever call you ball penis ?
Man what a treat to read. Thanks for sharing
When I was a kid, my Dad had a college class ring with a ruby in it, and I read in an encyclopedia (mid 80's at this time) about how early lasers used rubies and flash bulbs. I repeatedly asked to borrow my Dad's ring, and his camera (with a hotshoe flash) to try to create a laser. I was convinced I just needed to get the angles right to make it work. I had no clue what I was doing, or why I was failing, but God bless my Dad for indulging my interests!
This was my dream project as a kid. My World Book Encyclopedia 1965 featured it.
Awesome dad to let you experiment.
i had a synthetic ruby emerald cut, i had no idea if this was the same material as the ones used in lasers but i also had a camera flash unit that was battery operated and to make the flash go off there was a small button on the back of the unit, so i would put the ruby on the face of the plastic window in front of the xenon bulb and flash and look at the ceiling to see if i was getting any red shots lol i had no idea if something was working in terms of exiting the ruby but because of its emerald cut it is difficult to bother using mirrors and was hoping maybe id get lucky with internal reflections to do the trick
The amount of variables involved and the extent of how they interact is amazing. Before I ever get into electronics I truly will have to do my homework.
Duude, you are crazy, you build the things I wanted to build when I was 13, when I read it in my family's encyclopedia, I'm 30 but that was all I had back then. Loved your setup.
I cannot tell you how much I appreciate and need these videos even a decade later. Truly, Thank you.
I have a beautiful laser rod that's absolutely enormous - 25mm x 250mm (yep, about an inch diameter by almost a foot long) - made of Hoya Nd-doped glass. It was a spare single-pass amplifier rod from LLNL's Shiva laser array that never ended up being used, so when Shiva was decommissioned its spare parts were sold off and I was able to snatch it up. If memory serves (I did the math on this a _long_ time ago) it'd take about 7KJ of flash energy centered on 1080nm just to threshold it, and it could easily take 100KJ+ if properly set up (read: selenium-doped flowtube for better transfer, liquid coolant for less melty), which would produce an _obscenely_ powerful laser pulse.
One of these days I'll build a laser around it. I'll have to either get a metric buttload of 1080nm laser diodes or have a custom flashtube made to make it work though.
Oh, here's a piece of trivia that's neat to see IRL: Neodymium laser rods change color depending on the light source. In sunlight and incandescent light they're pink, but under fluorescent light they're purple.
Any luck building it yet?
I work with similar, but larger, Hoya glass rods. We use 12 "12inch arc length" 300 Torr xenon flash lamps to pump each rod. Might be able to help you answer some questions if you ever decide to build it
"Explosion Energy" -I learned that one the hard way. 2000uf,450V..too much for a cheap disposable camera flash-tube. Hot glass shrapnel. Oww.
I've been wanting to build a ruby rod laser since the 5th grade,I'm excited to see more. Science is fun! :)
Kept seeing Chris Tucker in my mind every time you said ruby rod. Great vid Ben, can't wait for what's next.
I've only read about stuff like this in books. To see someone going through the steps to actually build it is awesome.
I can't imagine this laser having much use but it will still be the coolest thing around
Oh my gosh...my dream project from reading my World Book Encyclopedia 1965 when i was young...glad to see him do it.
Ben, you have got to be the most interesting/intelligent people on UA-cam. Everything from super-critical extraction to homemade lasers. Dude, that's awesome!
Like the old school ignition coil next to your capacitors. Those are getting hard to find nowadays.
Way COOL!
Ok, my inner geek is showing, but then again, I am an engineer. ;-)
+Matthias Wandel:
I think all cars that have a internal combustion engine have them.
I have the same model as in the video but I think mine is damaged since I overheated it because I ran too much current as I was experimenting with it.
You can get a coil from any car parts store. Both of my trucks use that style coil.
The link to the xenon flash tube
Most new cars use coil on plug or coil packs or other things. Old coils like that are still around, but way less common than they used to be.
Once you figure everything out, adding a Q-Switch even if it is passive, it will make wonders. You will be able to hear ionized air when focusing the beam. It sounds like an electrical spark.
You will also need a series inductance to add some milliseconds to the discharge time. Lasing takes a little bit longer than the capacitor bank takes to discharge through the tube and the needed delay depends on the lasing media. Not sure about synthetic ruby, but ND-Yag needed about a 1-mS delay and lasing occurs around 1064 nanometers wavelength when using ND-Yag.
I regret selling my ND-YAG Laser rig to some guy in some university in Italia.
Laser flash lamps are sometimes doped to absorb...some of the UV, this improves efficiency since UV normally doesn't contribute to the pumping (at least for nd:yag) and also prevents UV damage to the rod (solarization).
Just put some of the flash lamps you have under UV light, some of them should fluoresce blue.
Nice setup, Ben. Looking forward to seeing it lasing.
The level and variety of your knowledge is admirable.
I've been doing my own learning about lasers and they are so interesting. Can't wait to learn more and understand better
Wow. you're the reason why I took engineering in university. Keep motivating
When I was a child, forty years ago, I read about ruby lasers and since then, I dreamed of owning or making one 🤯
Every time you say 'ruby rod' I think of the 5th Element. =X
Same
LOL!! Oh lord now I'm gonna hear it too!
I wonder what color of light is emitted by the Ruby Rod laser... My guess is super green.
(i know the real answer is red)
I wonder if it'd be possible to frequency-double a ruby rod laser. Of course that'd put it well into the ultraviolet instead. IIRC most green lasers work by frequency-doubling an infrared one.
Also I wonder if an emerald can be made to lase given the right light source.
Brett DiMichele Studios i know use a different chemical. more active
this video was fascinating. i only just learned about lasers the other week, sort of by accident, i was learning about voltage regulators, especially lm317t, and i keep reading about using them to supply constant current to laser diodes. so i bought some, and a few 2w lo diodes off eBay, with hosts, and some goggles. wow. after a few false starts i had a laser! popping balloons, lighting matches-did all that. then got some red diodes and bought a green pointer, and an x-cube, and played with making a white laser beam. i loved it all. i even bought a cheap fog machine off ebay, and the ingredients to make my own superior fog juice, to use with the mirrors i've glued to little pc fans and stuck to my study wall! now i want to use my recent high voltage learning to make flash-tubes work. maybe soon ill build a laser like this!
In my Engineering career I have spent as much as $100K on a single piece of equipment but I never get to buy stuff as interesting and fun as the stuff you have here. What fun! Thanks.
One thing you won't find in the documentation about series trigger is the circuit to keep the high voltage pulse entering the power supply charging the capacitor (and every other electronic plugged in the room).
Transient-voltage-suppression dodes of proper rating (or several in series) can normally crowbar the pulse at the PSU side.
Just keep that in mind if you do ever go there.
I wanted to build one of those when I was 12 years old in 1980. I almost built one 4 years later, but couldn't afford the ruby. Thanks for the memories. I didn't know about uv either with xenon.
UA-cam Most viewed/replayed parts in a video
ua-cam.com/video/QgN_Z4FXuOY/v-deo.html
The two video's mentioned:-
How To Make Ruby in a Microwave
ua-cam.com/video/ybcdRQmQcHQ/v-deo.html
Ruby laser design process
ua-cam.com/video/VSdUQ4oNKiI/v-deo.html
Sintered Barium sulfate (NOT sulfide! that one is poisonous) is used for diffuse laser reflectors, much much better then aluminum foil.
Yes. this is the same thing you drink for x-rays. pretty common substance.
Barium sulfate can also be painted as a water solution on surfaces, or wet formed in a mold then dried.
Of course you need 100% pure Barium sulfate, not the flavored one used for x-rays.
Very cool. I cant wait to see the final results!
Agree, it could be nice start for more serious device
Jaw dropped when I saw the rest of the capacitor bank.
I'd be interested in seeing a diode-pumped version of this laser. Blu-ray diodes at 405nm are really bright and cheap these days, and it seems like they would work more efficiently than a xenon strobe.
We watch this whole video waiting for the most exciting part, to see it in operation and then you say bye.
I can't hear "Ruby Rod" and not think of Chris Tucker's Ruby Rhod from The Fifth Element... Every time you say it. Without fail.
That's exactly the kind of laser with spiral tube I used to see on cartoons when I was a child. Always wanted to build one. Someday...
(until then, learning)
I love this channel because although I understand almost nothing, I am still engaged fully. You're amazing dude, I wanna have a garage like you when I get a house.
So, are you deliberately using the capacitor bank ESR and thin wires to act as pulse-forming network or have you not considered making one?
They greatly help to widen the pulse and keep it above lasing threshold, this way you can dump more energy into the laser itself instead of heating the flashlamp ;-)
p.s. you absolutely have to blow something up with that huge pile of capacitors (and make a video of course), I personally would suggest some cheap disposable camera flashlamp :D
For those suggesting using magnesium to charge the rod. Too much heat. Having it far enough away to deal with the heat would prevent it from lasing. The set up he has is optimal for a demo. The flashlamps that would typically be used for this would actually have their exteriors coated in a reflective substance so that they transmit more of the light where its wanted.
This is Ruuuby Rhod--Liiive from Phloston Paradise!
Another fascinating video Ben! You always come up with a new interesting subject to cover. That's one hell of an exciting lab you have there :)
I understand this is old so maybe my information is not useful but I am very concerned you don't know if your laser safety glasses can block the UV. Any reputable pair of laser safety glasses will have the wavelengths written on them that they block along with the optical density for that wavelength. It is a logarithmic scale so OD1 will block 90%, OD2 99%, OD3 99.9%, etc.. Typicallly, class IV lasers will use OD6+ at the appropriate wavelength. The glasses you show, if there are no markings, are most likely "welding glasses" which are not adaquate for lasers.
Very informative and professional video but would have liked a demonstration. Keep up the good work!
Would it be possible to use that laser safety glasses together with an auto darkening welding helmet? Just to avoid any IR/UV exposure to both skin and eyes. Or it will block the entire visible spectrum?
SOOO many caps. Man the fun you could have with them. BTW when are you going to do some cryo hardening of steel?
Excellent presentation and neat set up, keep up the great work Sir!!
Nice video! I always planed to build one! Is Erbium stronger than Ruby, if a rods os same dimensions are being used? thank!
Wow! Really looking forward to seeing more on this project!
Excellent explanation!!
I am used to see reaction chambers that enclosure the light source as well as the rod.. and probably it would be best for you to do one as well. It would protect you, it would protect the rod.. the light source .. etc. If you don't want to build one.. there is a guy on ebay from Israel that sell those quite cheap (i have seen them as low as 80 USDs - and some even have the old rod inside). Not to forget that high frequency light excitation will produce heat (such as the CO2 lasers do) and that should be dissipated within the chamber itself either by water or any other cooling technique.
Excellent video!! Keep on!!
Regards from Portugal..
New level of engineering badassery achieved: 1 MILLION
When pumping ruby the bluish region is color temp is favorable this usually matches high voltage and lower capacitance. Similarly, the YAG prefers to be pumped with lower voltage and larger capacitance for a more reddening of the pumping color--hope this tip helps somehow with capacitance choice.
Can't wait to see more of this.
How much did the ruby rod set you back? I'm guessing a couple thousand?
very informative! will it be necessary to use a pulse forming network to get a decent discharge curve and duration out of those caps?
Where did you get the mirrors from? What are their specifications? Are AR coated rods better than rods with external mirrors?
+Pulkit Sharma The first batch of mirrors came from eBay. I had an automatic search for "ruby laser mirror". They were not in great condition, and had some unknowns, so I also bought a new set from Eksma Optics. I believe really high power ruby lasers generally use external mirrors, where small/medium rods can have integrated mirror coatings.
I'm not gonna lie and say I understand the science behind this - but one thing I do understand is that you are trying to take a shitload of light energy and focus it into a concentrated lazer beam blast - a frikkin death ray. SIR, YOU HAVE MY ATTENTION!!! (And my subscription)
LASER
Light
Amplification ... by the ...
Stimulated
Emission ... of ...
Radiation
😎👍🍺
What's the advantage of using ruby? It seems like it adds a lot of complications so there must be something that makes it worth it?
I just wanted to say thank you! I really enjoy your channel! Thanks for sharing!
I love to watch ruby laser construction. Can you please tell me what size each of the large silver capacitors are (volts and capacitance).
Thanks so much,
i am basically sure optical pumping the ruby and dispersing them imaging would require 360 degree tranparency on the output and syncing the laser with a particle sensor with an r2d2 for forward expansion. And the lens effect to bounce back the processed image like those old binoculars
Whats a good starting point in doing these projects? im just starting college and have basic tools, a mini lathe, and a drill press.
I was waiting for you to turn it on.. Lol
When he said "this is not my final design" I knew he wouldn't turn it on.
HARIMA
Your discharge method for the HV capacitor bank makes me nervous. If the clip lead failed, the resistor would bring the screwdriver shank to the voltage of the capacitor bank. The length of the arc you drew from the bank when you discharged it should indicate the amount of respect you should give it. If you get this wrong once it will be the last mistake you make. Having worked with HV power supplies for years the discharge device of preference is a bleeder resistor that slowly discharges the bank after power is removed. A knife switch that can directly short out the capacitor bank before touching anything is also a good idea. One HV power supply I worked on supplied 8 KV at 5 amps, for protection it had mechanical interlocks that required the mains power to be removed, the input to the power supply to be shorted, and the capacitor bank to be shorted with a knife switch. The power supply had a bleeder resistor that took two seconds to discharge the power supply to less than 10 volts. Before working on anything a "Bang stick" which was a 4 foot long insulator with a metal hook connected via a heavy stranded cable connected to ground was touched to all high voltage points. This last safety device should never be necessary but will save your life should one of the others fail.
I use a "Bang Stick" to discharge the capacitors on our Uni's 4MeV Linear Accelerator (yeah, it's small but still lethal). Long (3 ft) Rod of Ebonite (!) and a fat ribbon of earth cable connected to the brass hook on the end. Once "Banged" you leave the stick hanging as capacitors have a sneaky habit of not discharging all the way and recover just enough to give you a another one when you least expect it. Great channel this one, keep up the good work.
Exactly what I thought when I saw it. And those cheap clip leads are notorious for failing.
You MUST make a better grounding/discharge system than that!
And/Or use bleeder resistors to discharge the bank to a safe voltage in a reasonable time (say, less than a minute).
Did the same while working on Navy Surface Search Radar. Add rubber mat, lineman gloves, and face shield; then you are good to go.
i'd love to see you complete this project sometime
is there any update on this i would love to see how its going on the progress of this laser.
Great video! Amazing project and very well explained.
your video are amazing. nice to see some intelligent content on youtube. thanks.
Would these capacitors work in a voltage multiplier configuration with diodes or is it to much power?
Can you also pump it with burning magnesium?
Of course, it is less controlable, but burning magnesium releases ~600kJ per mole of which a considerable part is emitted as light.
+Curixq:
It would probably work but you would need some strips of Mg ribbon all burning at the same time. Also, it burns too hot and might damage the ruby rod.
Another excellent video Ben.
I am working on a project with a capacitor bank of similar size and am trying determine the appropriate discharge resistor size. How id you decide what value and power resistor to use? Thanks
Love that they use a car ignition coil as an ignition device for the flash tube.
A fraction of that voltage would do but I guess if you want it to really go off in that brief second ...
Good day sir! I know an older vid you produced, but instead of the xeon flash lamps, what about those super bright LEDs now available ???? Huge available duty cycles, and even constant light sources. Mind you you may have to have the 'brightness' up to just below cascade, but if you could get it right to the edge, a simple brightness increase to trigger. Longer lase time ??? Just a thought
Is there a Vanta-white (opposite of vanta black) to surround the flash and reflect all the energy into the ruby?
The lamp is about 50% efficient. You could get 10% or more of the heat in the foil. I would calculate the J/gm in the foil and get the heat capacity and calculate the delt T. You might damage the foil. The foil touching the glass will make a good trigger for the lamp. If there is trouble with triggering people wrap very fine wire on the tube and use that for triggering. The reflector could be hogged out of aluminum and then polish. It won't be stable over time but for a lab experiment it would work.
Thank you Ben for your fantastic videos. Love this stuff and you are particularly gifted at laying out and presenting your tech experiments.
Sincerely,
John from Mt View
Question. I have a Donald Duck nite lite from the 70s. It only works in some outlets. If it lites in an outlet, it then flickers if the lites are turned off. It's not a light sensitive type. It says 1/4 watt and 120 volts on it. I suspect it has something to do w/ the wiring in the house, as it doesn't stop flickering if i point a flashlight at it.
So would the effective coherence length of this laser be about 1/2 the distance between the mirrors? Could you expand that distance and increase the coherence length (at a cost of efficiency), or would you need a longer lasing medium?
Question: If the photons inside the ruby go back and forth between the opposing mirrors and are all in the same wavelength, shouldn't them cancel each other out as they race into each other again and again? Obviously they don't, but I'd like to know what happens to destructive interference inside a ruby laser. Thanks.
Each high index (ruby) to low index (air) transition must be a zero-node. That is no EM field at the mirror interface. I would need to refresh myself for the proof, but this is the physical principle that makes laser light temporally (in-time) coherent.
Cool stuff! Take care! Peace ✌️ from Welland Ontario Canada 🇨🇦
Brilliant, you convey information so well Ben! Thank you :-)
great video as always, I'm really looking forward to the rest of these!
How come you don't have the business end of that ignition coil hooked up? you'll only get that 20kv from the center socket (the part that would go to a distributor) and only if you have a points and condenser system hooked up to it. By itself, you only have the positive and negative _power_ terminals connected, but not the high-voltage output.
Maybe I'm wrong, but I would imagine you aren't getting much out of that coil. Is there another reason it's hooked up that way?
Oh, sorry - when you zoomed in I was able to see the little wire leading off the coil. My mistake.
PS - all standard safety glasses (z87.1 or newer) are legally required to protect against UV light. That's why you wear safety glasses even under a welding hood.
don't you have a video of this project completed and show the laser working? could not find it on your ch
There's another way to get a high voltage pulse. Connect a switch and a power source across the primary of your ignition coil. Put a spark gap across the secondary. Close the switch and current flows through the primary storing energy in the magnetic field. When the switch on the primary side is opened, the voltage across the spark gap rises until it arcs across the spark gap. The size of the spark gap determines the voltage on the high voltage side. The current through the primary side determines how much energy is stored and thus the length of the pulse. By using an adjustable power supply and an adjustable spark gap you can adjust the voltage and pulse duration. The switch on the primary side should only be closed briefly and released to avoid overheating the coil.
Hey I have a question about charging up capacitors. I have a studio photography flash that has a 4 capacitor bank, all capacitors are put in parallel. This flash unit plugs into the wall, but somehow it is managing to charge the caps up to around 350 volts with only a 120 volt supply. There is no transformer on the circuit board so I am confused about how it is doing it. I tried researching it, but have not found much information. There are two smaller capacitors on the board rated for a high voltage (and they are not for the trigger transformer I don't think.) any idea how it's doing it?
Voltage doubler. Fairly common in flash units like that.
2:31 - there actually is one. A mirror that has elliptical cross section. Since an ellipse by its nature has two focuses, placing light source in the one focus will guarantee that all the rays converge the second focus.
Ah... shame on me, you talk about it right at 3:17.
Can a Tesla coil be used to trigger a Flashlamp? will a Telsa coil damage the capacitor banks?
I'm 43 and wanted to build one of these when I was a young lad, it looked so easy. just buy a ruby rod that's mirrored fully on one end and partially at the output end, surround with a flash lamp and a reflector and voila, laser light!!! Now I'm wiser I know its not as easy as it sounds, a lot of skills need to be learned before a DIY attempt will work.
Still, I used to drool at the He/neon lasers in the Edmunds scientific catalog, they were way out of my lawn mowing allowance money,
Don't know what happened to the once bright, budding future scientist to be. I'm thinking hormones distorted my thinking and I made the illogical decision that girls were more important than school. Fuck me! How stupid! Now I'm just a lowly "blue collar" electrician who even has to dig a ditch now and then! No cool laser labs or cushy office jobs for me. God, I wish I could hop in a time machine and tell myself that girls are evil and will cause never-ending useless drama, the pussy is just not worth it. Nevermind, some paradox will screw that idea up now that I think about it.
But hey, I did manage to buy the first laser pointer radio shack ever sold! In 1992 it cost $89, all for a stinking low power, maybe 2mw at the most, red diode laser. It took three odd N size 1.5V alkalines cells. I thought it was the shit at the time.
Confession time! I'm probably going to hear what an idiot I am but give me some slack, this was the early 90's and this laser was extremely low powered, a modern dollar store red laser pointer will make my early laser look like a wimp. Here it is, shortly after buying my $89 marvel of modern technology, A police helicopter was flying near me, running out of fun things to do with my expensive gadget I decided to see if I could see the dot against the side of the helicopter. Much to my surprise he noticed and hovered over my location and turned on his "ghetto bird" spotlight, this bright beam of light was trained on me for what felt like hours while I was cowering on the back deck of my parents house! Anyway, given the time and how rare lasers were I probably have the dubious distinction of becoming the first jackass to point one at a low flying aircraft. It scared me straight!
BTW, I still have that laser and it works. The batteries actually are the second set bought in 1993, they still hold a charge!
Chris Barth lying ass
Everyone looks back and says to themselves, "Man, I was such an idiot back then." Even so, you seem to have set a precedent.
Yeah, it's easy to know the basics, but actually putting it into practice is much harder. I can't count how many times I've tried to make a laden jar and get it to produce a spark without success.
Chriscom28 You must have grown up with Flintstones.
I made Leyden jars since i was 8,and i made my fist Van de Graff generator when i was 14 or 15.
Quite litteraly its a container wrapped with Al foil and a nail in the top.Fill with water and proceed to shock the shit out of you.
You probably didn't charge it properly,its quite hard to mess up something that simple.
Chris Barth - I also had a book as a young lad called something like 'How To Build Your Own Ruby LASER' with loads of B&W pictures of the ruby rods and flash tube etc. I used to dream of getting the parts and being able to put them together.
As it turns out, it seems like it was a project that would have been well out of the range of my meagre kids DIY skills.
That resistor looks like a corborundum ceramic resistor. That's an excellent choice. It's got alot of mass that will absorb the energy.
Would it be possible to trigger the laser using something combustible like magnesium or would it take too long?
you're like the kerbal space program of unadulterated science. you make cool stuff and watch it blow up or do cool stuff, either way you definitely have fun doing this...
Im pretty sure those helical lamps you have are for a Korad K-1 ruby laser.
Styropyro is making a ruby laser as well, but is using a much larger ruby rod i think. Most likely a lot more differences.
Coincidentally I am also working on the Ruby laser at the moment. I've got much smaller rod (6mm diameter), and it seems mine has lower doping ratio (much less intense color). I am hoping to get it working on 1000J or less. Can you post a link to the mirrors you use? Their color is... unexpected :-)
What happens when you use a secondary synthetic ruby like how an afterburner works on a jet engine?
if it's pumped and well synchronized, you can use additional rods as amplifiers. peak powers become very high though which tend to uncover any weaknesses in your optical elements (esp the rod, maybe why Ben's ruby had a crack on the end).
Hello, great video, I was wondering what wood was used for the lasers base (I want something that my makes my projects look a little bit more professional than plywood)
He's using plexiglass with the protective film still on it.
Still can't wait to see your next video on this topic!!! ;)
:O How did I miss this! ua-cam.com/video/ZUevWmUViJM/v-deo.html
looove this channel! informative and entertaining as always. cool, ty
Couldn't you pump the Ruby rod with UV laser diodes?
Very cool and interesting stuff dude, thanks for sharing
could you get enough energy into the rod using modern high power LED's? either strobing or full on...
I have to say I didn't know anything about arch lamp ignition, and to think I was looking into making some arch lamp drivers, I might have been frying bulbs without this information!
Was there ever a follow-up video to this? I looked around but couldn't find one.