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Sea Creature Provides Inspiration for Better Lenses
Frosty Inc. writes "BBC News has a story about a sea creature that may provide the key to improving the quality of optical lenses. Scientists are speculating that the study of this creature might lead to more than better cameras. They believe that this knowledge could be applied to optical fiber networks as well, greatly improving their efficiency and speed."
"...10 or 20 times better for optical communication."
Just what we need, 10 to 20 times more unneeded Dark Fiber.
Operator, give me the number for 911!
Doing a Google search for "Ophiocoma wendtii optical" came up with loads of articles about this, mostly similar, but some better than others.
A good one is from Physics Today.
Looking at the photomicrograph, you would never think "perfect lens". There are a bunch of bumps in a pretty random orientation. They can't be all focussing on the same spots.
While orienting the calcite crystals with the birefringent axis parallel to the optical axis so you don't get double images is a nice trick, Bell Labs is not going to be making their lenses from burefringent materials, so that trick won't be much use to them.
The other trick, using the "double-lens shape that closely resembles the shapes proposed in the 17th century by Descartes and Huygens to minimize spherical aberrations" is also nice, it would seem we have known how to do that for some time. (Aren't those two guys getting kind of old?)
I would speculate that the critter builds the lenses, and then the nerve cells and photosensitive pigments migrate to where the lens focuses the light. It might also modify the lenses as they grow, using feedback from the nerve cells. Perhaps Bell Labs can use similar feedback to get their optics the way they want them.
Aside from light gathering, it looks to me like this trick can work backwards also. You can economize on pigment containing cells by placing them only at the focus of the lenses. Now you can camouflage yourself by changing only those small spots to match your environment.
Free book: Science Toys You Can Make
Calcite lenses aren't new to sea creatures: nature came up with such devices in the Cambrian period (more than 500 million years ago) and installed them in trilobites. A typical problem with calcite is that it is exceptionally birefringent, so when a crystal is oriented such that you're not looking down the optic axis, the image seen through the crystal is doubled. Some trilobites apparently had excellent vision: trilobites would orient the calcite crystal so that they were looking down the optic axis in order to avoid doubled images, and would employ dual lenses to correct for spherical aberration. These days other sea creatures still use calcite lenses as well (not always nicely oriented lenses though).
I applaud nature for being so clever as to come up with advanced lenses roughly 500 million years before folks like Descartes figured out how to do the same thing, and I frequently stand in awe of what nature can accomplish. On the other hand, I'm often less impressed by newspaper reporting: why, for example, are the lenses on the critter in the article so revolutionary? What is so remarkable here? Why is this creature distinguished from all the other sea bugs that have calcite lenses in their eyes? Is it because there are more eyes? Do the lenses exploit some remarkable and previously unrecognized characteristic of calcite (very unlikely)?
Humanity will continue to mimic nature's innumerable innovations, but it's a lot easier for us to mimic and utilize them when we know what's special about them...