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158nm high aspect ratio silicon pillars across an optical surface — not sure why they refer to it as “simple”? For sure it’s a great idea that is not super comp

by xt00 5y ago

158nm high aspect ratio silicon pillars across an optical surface — not sure why they refer to it as “simple”? For sure it’s a great idea that is not super complex but yea would be interesting to understand how it would be made on different optical surfaces. Super interesting.

amelius 5y ago
I think "simple" refers to the user's perspective: "Now, anyone can buy a lens, put the coating on and use the lens without worrying about dispersion," said Ossiander.
flyinghamster 5y ago
I'd also wonder how durable the coating is, and whether or not it can be cleaned. That could seriously limit its applications.
- gimmeThaBeet 5y ago
  Assuming that I was looking at the correct paper, it looks like they are depositing a substrate and the pillars on top, and that's it. Internet disclaimer that I'm not an expert, I don't know how you protect the pillars without having the same dispersive effects that they are fighting. For example, image sensors have glass in front of the sensor (for both protection and low pass), and the pixels are at least an order of magnitude larger, and 100x the area. But, maybe you can just compensate for that as well. Looks like the pillars are 164nm tall, 610nm high, which is pretty big all things considered. So normal semiconductor cleaning methods are probably fine. But the ways you would clean a camera sensor for instance would be very not fine. https://www.nature.com/articles/s41467-021-26920-6.pdf https://www.nature.com/articles/s41467-021-26920-6.pdf
- earthscienceman 5y ago
  Durability would hardly limit the applications, the vast majority of optical coatings are inside things like camera lenses. Glass is a sensitive thing after all anyway. They don't put any of the sensitive coatings on the front element, it's essentially a glass covering these days. Eyeglasses are the only optics I can even think of that are regularly damaged and in contact with various hazards that can't really easily be shielded.
lmilcin 5y ago
I think it is simple because it is uniform over the surface of optical element. In optics things get "complex" when they are changing over the area of the optical element. These tend to be a real PITA because it is difficult to produce anything that is not uniform to astonishingly exact specification as they tend to be in optics. They also tend to require separate design for every optical system.
magicalhippo 5y ago
Everything is relative... The nanopillar silicon coating was made using the same commercial lithography tools as industrial semiconductors, making it easy to quickly apply these coatings to existing optical components and expand the applicability of femtosecond laser pulses. Using existing manufacturing equipment from a well-established field is surely a lot simpler than developing ground-breaking new manufacturing devices.

by xt00 5y ago

amelius 5y ago

I think "simple" refers to the user's perspective: "Now, anyone can buy a lens, put the coating on and use the lens without worrying about dispersion," said Ossiander.

flyinghamster 5y ago

I'd also wonder how durable the coating is, and whether or not it can be cleaned. That could seriously limit its applications.

gimmeThaBeet 5y ago
Assuming that I was looking at the correct paper, it looks like they are depositing a substrate and the pillars on top, and that's it. Internet disclaimer that I'm not an expert, I don't know how you protect the pillars without having the same dispersive effects that they are fighting. For example, image sensors have glass in front of the sensor (for both protection and low pass), and the pixels are at least an order of magnitude larger, and 100x the area. But, maybe you can just compensate for that as well. Looks like the pillars are 164nm tall, 610nm high, which is pretty big all things considered. So normal semiconductor cleaning methods are probably fine. But the ways you would clean a camera sensor for instance would be very not fine. https://www.nature.com/articles/s41467-021-26920-6.pdf https://www.nature.com/articles/s41467-021-26920-6.pdf
earthscienceman 5y ago
Durability would hardly limit the applications, the vast majority of optical coatings are inside things like camera lenses. Glass is a sensitive thing after all anyway. They don't put any of the sensitive coatings on the front element, it's essentially a glass covering these days. Eyeglasses are the only optics I can even think of that are regularly damaged and in contact with various hazards that can't really easily be shielded.

lmilcin 5y ago

I think it is simple because it is uniform over the surface of optical element. In optics things get "complex" when they are changing over the area of the optical element. These tend to be a real PITA because it is difficult to produce anything that is not uniform to astonishingly exact specification as they tend to be in optics. They also tend to require separate design for every optical system.

magicalhippo 5y ago

Everything is relative... The nanopillar silicon coating was made using the same commercial lithography tools as industrial semiconductors, making it easy to quickly apply these coatings to existing optical components and expand the applicability of femtosecond laser pulses. Using existing manufacturing equipment from a well-established field is surely a lot simpler than developing ground-breaking new manufacturing devices.