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Light transmission through blocked holes

This twists my brain.

Blocked Holes Can Enhance Rather Than Stop Light Going Through

Even if I imagine light as a probability wave or think about tunneling, this is more weird.

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Permalink Reply by Steph S. on November 23, 2011 at 2:54pm

ScienceDaily (Nov. 22, 2011) — Conventional wisdom would say that blocking a hole would prevent light from going through it, but Princeton University engineers have discovered the opposite to be true. A research team has found that placing a metal cap over a small hole in a metal film does not stop the light at all, but rather enhances its transmission.
Chou said the result could have significant implications and uses. For one, he said, it might require scientists and engineers to rethink techniques they have been using when they want to block all light transmission. In very sensitive optical instruments, such as microscopes, telescopes, spectrometers and other optical detectors, for example, it is common to coat a metal film onto glass with the intention of blocking light. Dust particles, which are unavoidable in metal film deposition, inevitably create tiny holes in the metal film, but these holes have been assumed to be harmless because the dust particles become capped and surrounded by metal, which is thought to block the light completely.
"This assumption is wrong -- the plug may not stop the leakage but rather greatly enhance it," Chou said.
He explained that in his own field of nanotechnology, light is often used in a technique called photolithography to carve ultrasmall patterns in silicon or other materials. Thin metal film patterns on a glass plate serve as a mask, directing light through certain locations of the plate and blocking other locations. Given the new finding, engineers ought to examine whether the mask blocks the light as expected, Chou said.
Conversely, Chou said, the newly discovered "blocking" technique might be used in situations when a boost in light transmission is desired. In near-field microscopy, for example, scientists view extremely fine details by passing light through a hole as tiny as billionths of a meter in diameter. With the new technique, the amount of light passing through the hole -- and thus the amount of information about the object being viewed -- can be increased by blocking the hole.

This has implications for microscopes. I use them in labs and classes - very useful study.
I appreciate the post!

Permalink Reply by Steph S. on November 23, 2011 at 2:55pm

Also telescopes - this study could advance optics. Great read!

Permalink Reply by Daniel on November 23, 2011 at 9:22pm

Changing the photon direction using an opaque material and modifying the general direction of photons by blocking specific locations thus enhancing light transmission is well known, am I missing something?

Why do you think a magnifying glass is shaped in such a way and we put lots of tiny scratches into glass (aka shine it)?

It just seems to match predictions of QED.

Permalink Reply by Ruth Anthony-Gardner on November 23, 2011 at 11:21pm

I can see how very fine scratches make light penetrate better, as when you polish a glass telescope lens. But that doesn't translate to this case in my mind.

Please explain how blocking all of the paths enhances transmission of light. How do you get from "blocking specific locations" to every single hole is plugged up makes the laser light penetrate 70% better?

Permalink Reply by Daniel on December 19, 2011 at 1:51am

Oh, sorry I didn't see your reply. I don't check the boards too often anymore.

The keyword here is blocking with an "opaque" material, this changes the amount of spin the photons will incur while in this material so that they point through the holes by the time they reach the material edges rather than in another direction.

I could be missing something but it seems like a very small instance of diffraction grating. If you really want learn a little about this topic then read this. It's ~150 pages and quite accessible.

Permalink Reply by Ruth Anthony-Gardner on December 19, 2011 at 11:25am

Wow! Thanks for the explanation.