17 replies to this topic

[RichA]

This is anti-reflection coating in a bottle. It actually drops the reflectance of uncoated glass surfaces from 4% to about 0.6%.  Apparently, the National Ignition Facility uses some thing like it because it can be stripped off with drain cleaner and re-applied, no vacuum chamber needed.  They do it because the lasers they have damage the coatings and they have to be renewed because the glass plates to too expensive to just throw out.

 

https://www.alibaba....0335087347.html

 

 

[Scott in NC]

Interesting, but I have doubts that it can be applied smoothly enough to not alter the wavefront of the optics that you’re applying it to.

[RichA]

Interesting, but I have doubts that it can be applied smoothly enough to not alter the wavefront of the optics that you’re applying it to.

Well, you can dip it, spin coat it.  Spin coating is how they apply it to the lens plates at the NIF.  I don't think it matters because the coating ends up very thin, just like a regular 1/4 wave anti-reflection coating.  It's not like some glue or something.  They give a shot of it in this video. 

 

https://www.imdb.com...ref_=fn_al_tt_1

 

https://coatings.ucolick.org/ar.html

 

Interesting side note;  the Keck telescope uses a giant version of an ADC!

Edited by RichA, 14 September 2024 - 09:36 PM.

[TOMDEY]

For a windshield or eye glasses... why not try it on something else first. I find it hard to believe that the layer will be uniform or bring the reflectivity at that surface to 0.6%. No harm in trying on specimens. The transmitted wavefront will pick up the NΔT distribution over the surface; in reflection, double that. I was a vacuum coating operator/tech/engineer/scientist for 12 years. Never worked the chemical deposition stuff though. My boss, who was a chemist, dabbled in those things... but to no avail.

 

OH! You would have to be able to strip off the old coating, if present. Otherwise, the liquid stuff will increase the reflectivity by ~frustrating~ the existing coating. I once made that mistake... with nearly disastrous results, before figuring out what was going on. I'm guessing if not applied properly --- might wind up looking like a soap bubble or oil slick. I actually researched this phenomenon to determine/measure non-contact the thickness of the tear layer on the human eye cornea. The context was Bausch & Lomb Eye Drops and contact lenses development. Pleases me that to this day, one of B&L's most profitable products is --- OTC and Prescription Eye Drops!   Tom

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[Jon Isaacs]

This is anti-reflection coating in a bottle. It actually drops the reflectance of uncoated glass surfaces from 4% to about 0.6%.  Apparently, the National Ignition Facility uses some thing like it because it can be stripped off with drain cleaner and re-applied, no vacuum chamber needed.  They do it because the lasers they have damage the coatings and they have to be renewed because the glass plates to too expensive to just throw out.

 

https://www.alibaba....0335087347.html

 

Drain cleaner is sodium hydroxide.  Sodium hydroxide etches glass.  

 

I am also skeptical about this providing a uniform layer. This is meant for your windshield.  A windshield is not an optical grade surface.

 

Jon

[TOMDEY]

And this reality regarding uniformity >>>    Tom

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[Jon Isaacs]

And this reality regarding uniformity >>>    Tom

 

"How to turn your favorite refractor into a Kaleidoscope."

 

Jon 

[jimeh]

This is anti-reflection coating in a bottle. It actually drops the reflectance of uncoated glass surfaces from 4% to about 0.6%.  Apparently, the National Ignition Facility uses some thing like it because it can be stripped off with drain cleaner and re-applied, no vacuum chamber needed.  They do it because the lasers they have damage the coatings and they have to be renewed because the glass plates to too expensive to just throw out.

 

https://www.alibaba....0335087347.html

This is just Rain-X. Don't put it on a telescope

[Dave Novoselsky]

Try liquid unobtainium, works like a charm

[RichA]

Drain cleaner is sodium hydroxide.  Sodium hydroxide etches glass.  

 

I am also skeptical about this providing a uniform layer. This is meant for your windshield.  A windshield is not an optical grade surface.

 

Jon

The windshield material is just one example of the stuff.  There is likely a professional optical product i've yet to locate.  I highly doubt the people working with laser optics, which are often some of the most accurate optics made, would use something detrimental to them.  In the video below, they explain it to a degree and show how the material is applied. 

 

https://www.youtube....h?v=0qT48BVsI84

Edited by RichA, 15 September 2024 - 08:09 PM.

[topomountain]

hey guys and gals

 

anything they sell on alibaba is lab tested and guaranteed to work miracles on your lenses

 

and for that matter, someone let me know how it does on your windshield!

[Jon Isaacs]

The windshield material is just one example of the stuff.  There is likely a professional optical product i've yet to locate.  I highly doubt the people working with laser optics, which are often some of the most accurate optics made, would use something detrimental to them.  In the video below, they explain it to a degree and show how the material is applied. 

 

https://www.youtube....h?v=0qT48BVsI84

 

I worked with Laser optics.  Some of it quite precise.  Some is not very precise.  That lambda/400 etalon was quite precise.. The optical windows in our ruby lasers, not so much.

 

Jon 

[deSitter]

hey guys and gals

 

anything they sell on alibaba is lab tested and guaranteed to work miracles on your lenses

 

and for that matter, someone let me know how it does on your windshield!

Rich is a pretty smart guy, snarking him is low-brow. This might be a great way to save an eyepiece with a failing coating. I would like to hear more., It is certainly possible a layer down to 1/10th wave might be deposited. Something with extremely low surface tension that will be drawn uniformly into an even layer by molecular forces. Rich is right, those laser optics people have huge budgets and don't suffer magic.

 

-drl

Edited by deSitter, 17 September 2024 - 11:45 AM.

[RichA]

Rich is a pretty smart guy, snarking him is low-brow. This might be a great way to save an eyepiece with a failing coating. I would like to hear more., It is certainly possible a layer down to 1/10th wave might be deposited. Something with extremely low surface tension that will be drawn uniformly into an even layer by molecular forces. Rich is right, those laser optics people have huge budgets and don't suffer magic.

 

-drl

It's only fair AR coatings can be applied this way, since you can also silver a mirror relatively easily with methods available.

I've got a 1930's 70mm apo lens, 3 elements, none are coating.  This could be a benefit for it.  I've also got a 4 inch Japanese achromat with deteriorating coatings that might need it.  Lastly, old C8's purchased without Special Coatings could be improved. 

[RichA]

I worked with Laser optics.  Some of it quite precise.  Some is not very precise.  That lambda/400 etalon was quite precise.. The optical windows in our ruby lasers, not so much.

 

Jon 

These optics are exposed to 500 trillion watts of laser power.  Because of that, the optics must be precise and dust free.

[Wildetelescope]

The windshield material is just one example of the stuff.  There is likely a professional optical product i've yet to locate.  I highly doubt the people working with laser optics, which are often some of the most accurate optics made, would use something detrimental to them.  In the video below, they explain it to a degree and show how the material is applied. 

 

https://www.youtube....h?v=0qT48BVsI84

So that video illustrates why one should not try this at home, even if you had a "professional grade" coating in a bottle, even if you have a spin coater in the garage.    Look at all the precautions taken to eliminate dust contamination, lol.    Serious question.  Out of curiosity, ARE the coatings applied to refractor optics applied via spin coating?   For some reason I have been under the impression that Vapor deposition is what was typically used.    Genuinely curious. 

 

Cheers!

 

JMD

[deSitter]

These optics are exposed to 500 trillion watts of laser power.  Because of that, the optics must be precise and dust free.

Dang that is many watts

 

500 trillion watts = a string of Christmas bulbs 10 billion miles long More than 2x distance to Pluto

 

-drl

[topomountain]

Rich is a pretty smart guy, snarking him is low-brow. This might be a great way to save an eyepiece with a failing coating. I would like to hear more., It is certainly possible a layer down to 1/10th wave might be deposited. Something with extremely low surface tension that will be drawn uniformly into an even layer by molecular forces. Rich is right, those laser optics people have huge budgets and don't suffer magic.

 

-drl

this was not a dig at richa, i have read many of his posts and look forward to his tests of this process should he try it....

 

im all for mc gyver scope mods.... im all for alibaba etc, its just also a risky thing to believe ANY hype or promises from any Chinese vendors... ive got some nice Chinese scopes, but hey the internet at large is full of hot air, and alibaba even more so, just a little harmless fun,

 

all due respect to richa and other folks pushing the envelope