Tech Ingredients - 2017-05-31
An overview of the optics for the high energy pulsed dye laser.
very clever making convex mirrors out of available concave stock! great way to engineer your way out of a shortage. I smiled when I heard that. keep it up :)
Very impressive I am about 6 months into learning everything I can about lasers in a slightly different manner I will be using components and free space lasers already manufactured just modifying them for my intended use.
I have to admit until recently I didn’t understand any of the terms you used but since I have taken the time to read a few books and had the opportunity to question several individuals knowledgeable in the field I am starting to understand everything and I can picture how it works as you explain it. I have only found a handful of good resources on the internet for someone who previously had no formal education on the subject.. I hope your willing to share all your knowledge I know it must of been pain staking and timely to learn or find that information but I know I would greatly appreciate it and I would in return share everything I have learned with anyone diving into the field.... surprisingly one of the hardest things to find on the internet is how to handle and operate high power lasers safely.. you would imagine that would be something easy to find information on..
I slept thru most of my physics classes. But i have no problem listening to you go on and on.
Where were you when i was in school !
Thanks!
I too was probably sleeping in school. That is not the place to learn anything.
Nice. best laser I had was an argon-ion 600mw laser at around 480nm. The power supply was massive, as expected for the late 1980's. The blue beam was absolutely beautiful.
Can you still see with both eyes? It's like they Ring calling to you......
In Photonics we had a 6-watt argon Ion laser it was a massive beast as well. :) Scary laser indeed.
Thank you for sharing this information. I have learned a lot about laseroptics from this channel. Kind regards / Hampus - Sweden
I'm born in 1966 so of course i have to love lasers (and Star Trek) ... :-)
So the Dye cell becomes a GRIN lens https://en.wikipedia.org/wiki/Gradient-index_optics with the added entertainment of a changing index of refraction gradient over time / temp / or other variables. Fun..
Full of great information, as always! Thank You.
Thanks!
Very informative again! I liked the description of evolution of your various technics to reduce or eliminate or compensate the thermal lensing effect. This make me wondering if in the industry, if they design the cavity itself to compensate that effect by making progressive inner diameter of the tube to the middle lenght..?
I haven't seen anyone try that, but all the techniques I described have been used over the years by various manufactures with the same trade offs. There are more "sophisticated" methods as well such as adaptive optic alignment and spacing of intracavity telescopic lenses to compensate for thermal lensing in real time. Also, a phase conjugate cavity mirror can replace the high reflector and this actually inverts the aberrations within the medium. These examples are the most exciting, but the huge increase in complexity make these impractical...it's no longer any fun!
Cool, we had a 100 mj per second to 2000 mj per second Nitrogen laser so we used a 5 mw of Neon Helium laser. I built a 100 mj per second 337.1 nm Nitrogen laser in Photonics and built a Nitrogen laser UV spectrometer for chemicals.
Just a thought, and if this is an original one please quote me on the patent.
Since you're using pressure as a trigger why not put a spark gap in a resonator chamber with a speaker? Then you can trigger a rapid change in pressure with a simple sound pulse! It 'sounds' like it would be a very rapid , predictable and reliable trigger setup.
The problem there is it would be an extremely "hair" trigger. Holding off the main pulse with air pressure and triggering by a reduction would have very little margin of safety unless the sound level was incredibly high. Even very loud sound generate a suprisingly small differential pressure.
@@TechIngredients yes, there definitely are practical considerations.
In just 5 minutes I thought of parabolics, a horn acting as a lever arm to change the distance of the gap, and perhaps something like a Venturi in a tubular electrode. Amongst other confirmations that would look deceptively simple.
But then the blatantly obvious dawned on me, as in sound doesn't travel in a vacuum obvious. Of anything I thought of, the acoustic energy isn't transferred as effectively at lower pressures. If one put the spark gap in a pressure vessel one would also have to decrease the distance and that also would increase the sensitivity.
Thank you for responding, if you didn't I probably wouldn't have thought it out so much.
And yes you wouldn't want such a hair trigger that you could just snap your fingers like Fonzie👍.
Of course if that is ever what you're going for, I would probably try a supercritical fluid, being fond of Rube Goldberg and such.
you are awesome,i try to understand everything you are saying and sometimes i learn the meaning of certain terms thx to the way you talk about them or describe it,,what kind of work do you do or is this juts a hobby? what is your background?
Thanks!
Everything we do is recreational.
@@TechIngredients "we"? do you have some kind of rec room lol well thats my kinda recreation all right,,but why so shy about your backround,im curious where you learned all these things,surely on your own and not in schools
Sparkle, shimmer, & shine. Glimmer, glimmer. Flash....ZAPPP!!! Sparkle plenty. I saw the light, lord. KAZAKKK!!!
Excellent explanations!
i don't understand how your concave mirrors function as convex, because the beam has to pass through back surface of the mirror, then after internal reflection pass through back surface again to escape it, right? but the whole point is to have first-surface mirrors that don't suffer energy loss in all those extra medium-medium transitions.
The back surface is flat and does not focus or defocus the beam. The concave front surface is only concave when seen from the front. It is convex when seen from the back. It doesn't matter if the light is passing through air or glass when it strikes the reflective coating.
@@TechIngredients but on the way back from within the glass, instead of escaping the glass, the ray can get back scattered on convex mirror again due to internal reflection, effectively striking internal convex surface twice(or more) times: on this diagram i've used an arrow to show the interface that can create this parasitic Fresnel reflection: --> [<-(
is that not a problem?
Plz complete daigram on this project .daigram with itredigent to helpfull to understand
I've always been fascinated with optics but I found it's a very difficult topic to learn anything about. I'd really like to learn what I need to know to work out the specifications of the lens and where to stick it to achieve the desired result. Any chance you could recommend a book?
I would say order lenses with different focal length, get a low power laser and a fog machine and have an hour of fun learning how it all works and how different combinations produce various results
Also wear eye protection until you're sure you wont flash your eyeballs
how about using diamond pin hole? thats what they use for high energy beams or femtosecond laser ,or if they have mirrored
That's reasonable.
What is a "Plain old, Plain old cavity"?
Ha, my poor pronunciation!
That was a plane "O"/plane "O" cavity. This is an optics short hand for a cavity that has two plane ie flat mirrors on each end.
Was there a specific application for this laser? Doesn't this really long cavity require often realignment? Impressive.
Thanks! The application is primarily for the development of the laser itself. Alignment stability is not bad. The gain is so high and the structure is pretty robust in a controlled environment.
They are trying to explain this electron acceleration as some kind of diffraction. A visible laser cannot accelerate electrons in the direction of the travel of the laser beam according to some sciencevsettled back in 1979. But if two electrons accelerated perpendicular to an laser beam focus collide and bounce in opposite directions with great enough acceleration they will create two xrays in the direction of the travel of the laser beam which can then accelerate electrons in the direction of the travel of the laser beam according to Compton scattering.
If you wanted a low powered laser to operate at 400hz, how would I go about it? Would I purchase a specific laser or would it be cheaper to build it myself? Thank you sir.
The laser is the easy part, and I'd use a diode with the wavelength you need.
The driver can be a simple current limited circuit with a transistor based switch, with an optional SCR added, depending on the power requirement.
@@TechIngredients Thank you very much sir.
"A laboratory accident away from a supervillain."
Loving these videos. Can't wait to see the laser in operation! Approximately how much power does this laser generate during normal operation? I believe you mentioned 50 joules per pulse previously, but I don't know (or recall) the pulse duration so I can't convert to Watts.
Average output power wont be higher than 200A x 240V * laser efficiency ! =))
With the better optics, the maximum pulse energy is approximately 100 J. This is a relatively un-precise measure, because I had to use a liquid calorimeter and fire 10 pulses into it to make the per pulse estimate. The pulse length at 1/2 maximum is 20 usec.
So, about 5 megawatts in the pulse center. :)
I think I missed something, why not using a very low power laser pointer for the alignement beam? (in the beginning of the video)
The quality of the beam out of the HeNe laser is higher.
And what is the purpose of that laser?
To lase.
Duh! It's for the Death Star obviously. You people so slow and unimaginative.
Dave Nope. No mention of kyber crystals.
Destroy Satellites MIRACL Style
lunar warfare
Really interesting but can you turn it on and pop a balloon or burn a hotdog please?
thank you.
One question about using concave dielectric coated mirrors in reverse to get a convex mirror: Damage threshold is significatnly lower because of the carrier substrate (quarz) that needs to be passed right?
No.
Speaking of gas atmospheres, I was watching how MIT was producing graphene using a hydrogen atmosphere a copper sub straight and a oven to bake on the carbon to the copper using an oven. Why don't they use a laser instead of an oven?
The process is slow, at least it is for now. The temperature also needs to be stable. The oven is well suited for that and there are no clear advantages to a laser as a heat source.
Tech in gradients
If you send the outgoing pulse again through the new similar but different setup what it will be its consequences.
That will be an MOPA or master oscillator power amplifier design. This is often done to reach extremely high energies.
Good work
You and Styropyro need to get together.
Can you share your mirror vendor/source? I been shopping for 2100nm OC mirrors, only found two sources, too pricey. Are you using FS(fused silica) material?
Sure. A good source for reasonably priced optics is Eksma optics. They are located in Lithuania, but have distributors all over the world. For significantly less "reasonably priced" optics, REO makes some incredible super polished mirrors.
@@TechIngredients i had a spherical plano convex lens of 6" but sadly i droped it and it developed an inner crack,still one piece and still work but i am wondering if you know a cheap vendor for such a sized lens and preferably an aspheric one,,i am simply trying to use a home depot single die led white light with a pin hole in front of it to get spatial coherence and then collimate it with the lens ,,my goal is to make a spot that remains as small as possible over long distance ,just a poor mans laser among my very multiple projects ,would you have any tips on where i can find such lens and also tips of what i can do to improve the divergence and reach the limit with this equipment or whatever else you may suggest for me to get this long distance beam?
Microradians? I think I just lost a few brain cells thinking about that one lol. What would the MOA (minute of angle) equiv. of that be?
One radian is approximately 60 degrees of angle or 3600 arc min or 216,000 arc seconds. One micro radian is approximately 0.2 arc seconds.
Only 10869 views ATM. Where is this world going to?
Share this video and that will help. YouTube does not promote a lot of material that isn't pop culture.
Raman spectrometer, please! :-)
Let's be pals. We will steal the moon!
I'm game. Who do you think will buy it.
I swear, putting the word "laser" in the title is just like Chekhov's gun. If you say it's a video about a laser, you have to FIRE THE LASER!
I understand, but remember this is one of several videos covering the major systems of the same laser. We do fire the laser in the main overview video.
I support law enforcement and this is a crime.
What?
@@TechIngredients just, I support law enforcement, don't commit crimes, okay?
Talk ... talk ... talk .. and only at the end does he say this is the second video where I don't tested it ? Should put a link to the first video , we can just SEE what happening rather then take 18.00 to explain it . (friendly tip ) he's gota have 150K $ wrapped up in test equipment and hardware !!!
You make a valid point. Understand that building and designing these projects involves A LOT of research and believe it or not, I am holding back. I want to share what I have learned, not just demonstrate it. But, to keep things interesting, we will mix in some videos that are shorter, leaner on the explanations and show some useful demonstrations. Thanks for the feedback.
Excuse me for my " shortness ", of my comment , I just really wanted to see it , because I NEED to see it to understand in a more complete explanation , I'm working with micro dichotic mirror mounts , and some beam noise suppression optics , soo much to learn !! and a relatively inexpensive universal optical laser power meter .Your videos have been very helpful . So I do learn and enjoy , but demos with explanation , and repeat can be a very effective teaching technique . :)
I work on lasers every day and learned a few things from this great video. ALL the info was useful and well explained. I loved each of the 18 minutes!
Rod Sims This is a learning channel, it's not a whiz bang boom channel. Maybe try learning something.
You know why boys quit school before they graduate ? Because teachers are boring ! Boys are practical and manual ! You can talk about you laser for hours ! If you don't show "practical" stuff you lose me !
There are many reasons why boys quit school before they graduate and boring teachers are indeed one reason. Good teachers ask questions that make you think and in the process cause you to reevaluate your assumptions. What do you mean by "practical"?
Tech Ingredients how to electrocute yourself or blow a hole in your hand on a similar setup of course. Some people just aren't interested in learning how parts come together, and take no joy in planning, then executing and seeing the plan create something.
@Alexander_Sannikov - 2019-07-21
watching your laser vids reminded me of a He-Ne laser that i found in our university refuse pile. as a physics project i offered to try and resurrect it. mirror mounts were all bent and dusty, power supply was not working. after fixing them, i started adjusting the optical resonator with a green laser to make sure that mirrors are perfectly parallel. and you can imagine my joy when at some point dim green beam point that i used for alignment suddenly turned red as it started lasing
@TechIngredients - 2019-07-21
Yep, been there a few times!