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Blackest black material from MIT

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#1 Littlegreenman

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Posted 16 September 2019 - 02:36 AM

MIT engineers have developed a material that is the blackest black material so far. Vantablack was developed in the UK over 5 years ago, but the new MIT material betters it by absorbing 99.995% while Vantablack absorbs "only" 99.96% of light.

Both are based on carbon nanotubes that are aligned vertically on a substrate.

Do I suspect a patent lawsuit in the wings? I can't tell. It's too dark over there. (sorry)

Of course the is a point where chasing after the "x-est", such as smallest, cheapest, fastests, etc, gives you no practical benefit.

 

http://news.mit.edu/...terial-cnt-0913

 

https://en.wikipedia...wiki/Vantablack

 

 



#2 TOMDEY

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Posted 16 September 2019 - 06:39 AM

The challenge is interesting for its own sake. Like nearly everything else here, I had some exposure to closely-relateds. My experience was the (natural!) surface of the Moth Chitinous Cornea... back when I was collecting insects for the Dept. of Agr. circa 1970-71, in the jungles of Panama. Electron microscopy reveals that the surface is entirely covered with tiny little protuberances on a quasi-hexagonal matrix. They stick out like little icicles orthogonal to the macroscopic surface topology. They provide two advantages: 1) prevent dew from forming, 2) profound broadband antireflection. I did a bunch of math modeling to compute the ARC properties... also measured. White paper "Reflectivity of the Chitinous Moth Cornea."

 

I later resurrected that experience to research and develop ARC coatings for lenses at Bausch & Lomb. My boss was a chemist, so did plenty to come up with concoctions that would mimic that sub-sub-micron surface. (Must be many wavelengths long and sub lambda wide... = icicles!) Well, we produced that and here is the inexorable problem: extremely fragile, can't be touched, can't be cleaned --- ever!

 

This would also be true of the carbon nanotubes black stuff. So, as a surface treatment for telescope parts... might not be practical... but still of great theoretical interest!    Tom


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#3 TOMDEY

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Posted 16 September 2019 - 07:01 AM

Oooh! I just noticed the quote from John Mather. He was (of course) leading the technical aspects of JWST build, which I was also working on. He mentions the utility of ultra-black materials for Coronagraph "Planet Finder" missions. That would indeed be a great application consideration... what we would place the shade far from the imager, between it and the target star (which is occluded by the mask)... with the planets "sticking out" on the sides. Analogy is shading your eyes from the sun... with your hand! So... treating that deployed umbrella surface would certainly be an interesting consideration. Here are a couple charts from a talk that I gave on that. >>>   Tom

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#4 luxo II

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Posted 16 September 2019 - 07:41 AM

Tom - the petals around the edge of that external star-shade - were those an attempt at apodisation ? Did it work ?

 

Given that its a treatment that can be applied to aluminium suggests its not entirely useless - it could be useful as a coating for the inside of baffle tubes for SCT and maks, which should never be handled... likewise the inside of the draw tubes for crayford focusers and star diagonals, maybe a premium eyepiece.

 

Having seen how much moonlight is visible on the end of the baffle when my mak is aimed at the moon I wouldn't say its pointless; some of that scattered light manifests itself at the eyepiece by making the blackness of space at the lunar limb not as black as it appears in a very good refractor.


Edited by luxo II, 16 September 2019 - 07:48 AM.


#5 TOMDEY

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Posted 16 September 2019 - 09:48 AM

Tom - the petals around the edge of that external star-shade - were those an attempt at apodisation ? Did it work ?

 

Given that its a treatment that can be applied to aluminium suggests its not entirely useless - it could be useful as a coating for the inside of baffle tubes for SCT and maks, which should never be handled... likewise the inside of the draw tubes for crayford focusers and star diagonals, maybe a premium eyepiece.

 

Having seen how much moonlight is visible on the end of the baffle when my mak is aimed at the moon I wouldn't say its pointless; some of that scattered light manifests itself at the eyepiece by making the blackness of space at the lunar limb not as black as it appears in a very good refractor.

H, luxo! The sunflower petals are quite interesting. They are optimized to control diffraction, which would otherwise, necessarily, inexorably... send a bright spot right downstream onto the detector/imager entrance pupil (which would look like a terribly bright edge on the shade) --- those volutes combine phases to snuff that --- think I got that right...    Tom




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