Les' Lab - 2020-07-04
Episode 4 #laser #optics Check out my other videos: https://www.youtube.com/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: https://patreon.com/leslaboratory Or donate directly: https://paypal.me/leslaboratory Alternatively, please share this content on your social media platforms, it really helps me out! Apologies for the low volume. I will boost the audio next time! A tear down of an LSI Nitrogen Laser: 36kW Peak Power 150uJ 4 ns 3mW average power @ 20Hz This laser is re-assembled, then used to pump a small home-made Dye Laser. Nitrogen Laser manuals are here: http://www.337nm.com/Literature_VSL337_NitrogenLaser_LaserInnovations.htm Lambdachrome Dyes Datasheet is here: http://www.chem.ucla.edu/~craigim/pdfmanuals/catalogs/Lamdachrome-laser-dyes.pdf
Very interesting had never heard of a nitrogen laser before so interesting to listen to you talk about it.
Thanks for your feedback! I have recently uploaded another video on home made Nitrogen Lasers as well at: https://www.youtube.com/watch?v=pCnXftuJ9Zo
@@LesLaboratory i already watched it, i liked it very much
@@saltyaustralian8661 Awesome!
I love anyting that has killer joules.
Then you will love the next video!
Very interesting, I have the bigger brother of this model, the VSL-337ND-S. I've plans to make a dye laser using it as a pump, so your setup is useful to see.
Great! Go for it, it is a nice little project. I am going to replace the HR with a diffraction grating at some point to make it tunable.
i made the circuit for hene laser(without capacitors because i dont have)but with a more voltage tube lasing.thanks for this design. output decrease in intensity when the tube heating up?
This question was asked previously. Such a power supply absolutely requires filtering capacitors and current limiting, else the tube will become unstable and/or fail. There are no shortcuts unfortunately.
It might be the titanium dioxide that is added in paper that you see as blue. I don't think they would use coumarin in paper. I also see this fluorescence in white plastics that are dyed with titanium dioxide. I would have to check but I think coumarin like many other dyes needs to be in a solvent for the molecule to be in the right configuration for fluorescence.
Thanks for watching!
You are right, TiO2 is used in paper manufacture as a brilliant white pigment, but its primary mechanism is as a bright pigment, rather that as a fluorescent compound. Although TiO2 does fluoresce, its quantum yield (~0.2) is poor in comparison to Coumarin dyes (~0.73) also the peak fluorescence emission of TiO2 is around 350nm ( in the UV).
TiO2 is primarily used as a brightener because of its highly reflective properties. Believe it or not TiO2 can reflect more light (around 99% in ideal circumstances) than a regular aluminized mirror, , and for this reason, is often used a a diffuse reflector in flashlamp pumped lasers.
Coumarin will quite happily fluoresce when not in solution and is used in paper manufacturing and laundry detergent as an optical brightener, which is why white clothes will fluoresce brilliantly under UV. Is is in fact possible to get liquid laundry detergent to Lase in a dye laser cell!
Stay tuned, I will be doing a teardown on a bigger N2 Laser (once it arrives) ;-)
@@LesLaboratory Interesting, I will have to look for some information on it. I have not read an MDS on coumarin so I wasn't sure of it's toxicity/uses outside of scientific applications.
I did a quick test just now with a mini TEA and 355nm laser and you're correct it does show some fluorescence in it's dry state. I am actually a bit surprised because the most dyes seem pretty inert. Bad assumption on my behalf on that. As I said, I am just getting into dye stuff.
I did not know that titanium dioxide was used in flash lamp assemblies but now that you mention it I think I have seen what look liked white ceramic in a YAG once, but just once. I'll have to take a gander when I am back at work.
I will certainly stay tuned for more videos, you certainly know your stuff and then some. Now when you say bigger, like is this a laser that needs a cart? lol I should send over some pictures of the N2 laser at the shop I work at that is being rebuilt. You would get a kick out of it I bet. Nothing spacial but it has built in gravity.
Would be awesome if you could boost the audio of this video. I can barely make it out, then when a advertisement pops up it scares me half to death. Even though it’s one of your earlier nitrogen laser related videos… I really like it and I think it’s a really useful video
Yeah, it sucks. It was an old one shot on a DSLR that didn't have a high gain mic. Unfortunately, there is no longer an option in the YT studio to boost the audio :(
Any recommendation for materials for the 50/50 beam splitter & specifics for the collimating & quartz cylinder lens you use? I'm setting up a system similar to your video last year on Super Continuum. Not an optical engineer but have spent some time working on camera systems. I wear my rated safety glasses and lock the room I'm doing my assembly work in.
i have for he ne laser power supply wire(0,6 mm with insulator) for 20 turns to ferrite core . it is good?
Yeah, that should be ok. For ZVS drivers I usually use the thickest I can find that will physically fit.
Question: awesome educational video my question is I was luckily to inheriting the laser cartridge without the circuitry so is there other way to power it manually can I used power source such a variable transformer or ignition coil driver ?
Hi, yes you can power those with a home made HV DC power supply. The cartridges don't require vast amounts of current. Ignition coils are not really suitable as the cartridges expect smooth high voltage DC. A better bet would be a ZVS driver and a small DC flyback. You must limit the output current with a large value resistor, maybe 10Meg to 50Meg. See: https://www.youtube.com/watch?v=GbQEan4gwWM
To power the cartridges, the black wire or case is ground, the larger HV connection should be supplied with 17kV and the smaller HV connector is the trigger (a few kV).
@@LesLaboratory thank you very much for that info I appreciate it
Are you sure the Nitrogen laser is producing a 4.5ns pulse? 4.5ns is pretty close to the limit the 50MHz scope can resolve. I would also expect a different pulse shape here. Exponential growth followed by a somewhat slower decay.
Yes, according to the spec it is, however this is not how energy pyroelectric sensors work. They do not measure in the time domain, so the pulse with and shape are irrelevant, only the height, which translates directly into joules. See the literature of Gentec EO page.
Follow up from my answer, the application note is here:https://www.gentec-eo.com/Content/downloads/application-note/AN_202203_LBM_201.pdf
@@LesLaboratory I was actually referring to the Photodiode you use for the pulse measurement at 12:30 . with the 1Gs scope you're using that only gives you 5 data points along the entire pulse, so I would be at least skeptical about the shape of the pulse.
@@Farathus ah right, sorry yes, I get you. The scope was hacked to 100Mhz, but still not enough as you say, unless you do repetitive sampling. I have just bought an old Tek 5000Mhz that is hackable to 1GHz for precisely this reason, so stay tuned!
great video! Do you have any idea what the degree of coherence the nitrogen pump beam is, say compared to a laser with a traditional resonant cavity with mirrors?
Coherence length, probably on the order of a few mm. You can do diffraction experiments on a small scale, but you won't make a hologram with one. Even with a real cavity you won't improve things significantly. That said, as a pump source for dye lasers, or for micromachining, they are awesome!
@@LesLaboratory I'm really intrigued by your bayer filter removal video. How hard would it be to couple a quartz fiber bundle to a home made nitrogen TEA and replicate your efforts? That is really an astronomer/photographer's dream :)
I can t acces the pages.What is this simpler design(your charge transfer or design with 2 equal capacityes)
I like more to make your design with doorknob capacitor.With an atmosferic spark gap, and atmosferic laser channel(i don t have N2), the laser (charge transfer design)will lase?I need to know because i want to buy a doorknob capacitor and is expensive
Capacitor have 40kv 1000pf.i don t found acetate ,It will work with copiator transparent sheet?
If you want everything to run at atmospheric pressure, try the simpler design as I suggested. Do not attempt more complex designs until you understand their quirks.
3:07 can you elaborate it plz , does helium Mixture used in co2 laser serves as same purpose as used in this laser !!?? Plz tell
More or less. In the Nitrogen Laser Helium is simply used a buffer gas that negates the need for a high vacuum, and also helps with ionization.
In CO2 Lasers, it helps the CO2 Molecule relax back down to the ground state, aids ionization, and because it is thermally conductive, helps dissipate heat.
@@LesLaboratory thank you
so i dont presurize with air, and N2 is expensive for me.is more good to use aprox 5cm rail spark gap instead simple gap?Or i should try first with simple gap?
Try with a simple gap first, then if it works, refine it.
It will work with copiator transparent sheet?I tryed simpler design 12 years ago, before the accident and i havent a good result. Maybe is good to try charge transfer design in open air with more succes.I colaborated with Ben Schweitzer and he said (the spark gap longer might work)I don t found acetate ,It will work with copiator transparent sheet?i don t found acetate .If it works I tell you and Ben.
See comment above: You might get away with 100 micron for a short while. Stacking sheets is not really a good idea for many reasons. You might find overhead transparencies will work just fine.
i cant buy high voltage resistor 20Meg but it will work with 20 resistors(1Meg 3-5W) in series to obtain 20Meg?
Yep, that should work. Look for reasonably high voltage rated ones though (>1Kv each, pretty common)
Do you think it works with the spark gap longer at atmosferic pressure?t want to construct a simpler spark gap because i am a person with dizabilityes and is very complicated to me to construct your spark gap To know,the person in that picture is my mom.I have 32 years and i want to construct my tea laser(your design) with my mom and my brother help..
It will work with a simple gap, however you will not get the same performance. If you want a good, simple design, look here: http://www.jarrodkinsey.com/pages/howtobuild.html
Please take care when building these things. The emit considerable UV and noise.
it will work the presurized spark gap with air from a tiny compresor ? will not appear condens?
You would need to remove the moisture from the air. When you compress air, water precipitates out.
when i stick the aluminium foil to plastic sheet, i want to use a small quantity of glue to the corners aluminium foil to stay in place. it is good?
Static electricity will hold them down. I never use glue.
Hi, thank you for the wonderful channel, I’m new to dye laser, is the bottle with liquid the dye laser? Does it change the laser wavelength? can you share some thoughts about is it possible to generate 355nm laser with it? or it has to be done KBBF? thank you so much!
So it work without the capacitors? Because i dont found in Romania these capacitors.I have a hellium neon laser tube 7,2mw power.I could use a resistor balast(80-100k)in series with a chain diode(20at 1000v 1A or5A)?
I use a flyback from a plasma globe without diode inside.
You need the capacitors for smoothing. You should be able to pick up surplus HV stuff pretty easily on eBay or surplus houses.
How could you predict the wavelength of the output beam based on the input beam wave length and the dye properties?
You could predict Wavelength by looking up the emission spectra of the dye (this would give the wavelength range) and you could calculate the angles required for the grating.
i don t found acetate at 190 microns.Is good with two sheets of acetate at 100 microns result a 200microns sheet?Or i can use copiator transparent sheet?
You might get away with 100 micron for a short while. Stacking sheets is not really a good idea for many reasons. YOu might find overhead transparencies will work just fine.
i dont found aluminium bars for laser channel. I have brass.It will work with brass or stainless steel?Will not have burnmarks trought the cannel in time or something?
I have not tried it, but it will probably work just fine. You might find with brass that you have to clean it more often, as the oxide builds up.
the power supply will be a mini tv flyback (15-20kv DC) or monitor flyback.what kind of resistor i can use to protect the supply ?if it need it.i dont see very well in clip, which side of aluminium foil is better to put down to the plastic sheet(like mirror or diffuse)?
I use high voltage 20 - 50Meg Ohm resistors (made by Vishay) to limit current in my designs. They are expensive, but may appear on eBay from time to time.
Dont you have to adjust the distance between the mirrors when changing dyes?
Nope, just the angle of the diffraction grating
Hey what instruments do you have on your bench? I see a few oscilloscopes and maybe a DMM. Tell us what you have. I am seeking instruments and would like to see what others have. Is there a surplus or clearance place where you get lasers like this one? I worked at a laser company, but that business is defunct now. If I had my hands on one of their lasers it would have been put to good use.
All sorts of equipement! A Hitachi V222 Scope, the Tek 2232, A Rigol DS1054Z, power supplies (riden), function generators, a little Tek 222, Logc analyzers, CRT monitors, Serial Terminals etc etc, etc. Perhaps I should do a lab tour.
All my Laser surplus these days come from eBay these days. There used to be surplus shops in the UK that did this kind of stuff, but not any more, or t leas not at prices that interest me.
Need some current?. I'm free of charge.
i found transparent foil at 125 microns. It is good?
It might do, its a little on the thin side, but should last a while. Just try it :-)
for the resistors ,which is better 3w or 5w ?
That depends on the output of your power supply, and you will have to work that out. Building Lasers can be a dangerous undertaking. You should not attempt to build one unless you are absolutely certain you know what you are doing.
i found at 200 microns plastic sheet for tea laser.it is good?
It's probably fine. Try it!
about your helium neon laser power supply, your curent from the flyback is DC or DC in pulses?
DC. There is probably plenty of ripple, but I'm not putting my scope near it! The output is smoothed by the huge caps anyway.
resistor 120k 5w what is for?
Pulling the peaking capacitor to 0v
Does the spectrum of nitrogen laser has a single peak at 337.1 nm?
All atoms/molecules have multiple emission lines. Whether or not they will Lase is another matter. The 337.1nm line in N2 Lasers has extraordinarily high gain, and will suppress Lasing at other wavelengths. I believe the literature describes one or two other UV Laser lines, and one visible Line, but these are of limited practical use.
@@LesLaboratory Sorry, I missed a word "laser", I mean the spectrum of nitrogen laser. I got it, thanks for your answer.
you wear safety glasses ?
For Nitrogen Lasers you can use plain polycarbonate safety glasses. They are opaque at 337.1nm
can i have your email id, so that i can contact you as i am doing research in Microwave Photonics for guidance
@viorelaalexandru361 - 2021-04-18
Ten years ago, before the accident i builld two nitrogen laser ,first with longitudinal excitation and the second it was a TEA laser with equal capacitors.For LE laser discharge i use a capilary with 1mm hole and10cm long with thin windows at the ends.I made low pressure with a seringe.Disadvantage was ozone forming after 15 seconds.My power supply it was a plasma globe flyback transformer (10kv AC high frequency) and it work with acceptable results.For tea laser the results was very low because i use a high inductance spark gap (my spark gap had long wire)and i use a lot of glue to capacitor .At that time i don t know the trick with low inductance.This is my experiences with nitrogen lasers.