Wednesday, November 23, 2011

Uh oh, that fly has a wafer-scale camera

..John Wallace
..Senior Editor
..Laser Focus World

Predictions for the future of humanity range from an expansion of the human race throughout the universe to a quick self-extinction based on nuclear war or biological agents. On a just slightly less-grand scale, some prognosticators say that within a few decades we will have melded with machines, our thoughts and memories flowing throughout electronic or quantum-optical circuits. (Others would say to this, "Bah.")

But what is next, really? I'll just make one prediction: the rise of lethal nano unmanned aerial vehicles (UAVs). Here, "nano" means the size of insects. Hummingbird-sized UAVs have been around for a few years, as have those the size of dragonflies.1,2 Real insects are also being turned into flying "cyborgs" for various purposes.3,4 There is now even a technical journal devoted to the topic: the International Journal of Micro Air Vehicles.5

Larger UAVs, of course, some quite lethal, are already in operation. But the smaller ones have been described mainly as sensing devices, often for surveillance. The ideal, which I believe will be achieved within a few years, is to shrink them from the size of a dragonfly to something much smaller -- say, that of a housefly or mosquito.

For example
But a mosquito does more than sense its surroundings; it also can deliver an itch-causing toxin to a human or animal. Perhaps all a nano UAV would need is a needle and some toxin to take out a target. Or a fly-sized surveillance nano UAV could work in concert with a larger, more lethal nano UAV. All this would hinge upon getting enough power to the UAV (such as in Ref. 4), and creating optical sensors small and light enough to be carried along. Wafer-scale cameras fit the bill nicely.

Through-silicon-via technology enables
low-cost CMOS cameras smaller than a
match head. (Image: Awaiba GmbH)

I'm just making a guess (meaning I have no insider info!). Is my prediction an obvious one ("Anyone coulda guessed that")? A lunatic one (“Here’s a tinfoil hat for you, young fella”)? I don’t know, but I’d love to hear from Laser Focus World readers about their own ideas for what strange photonics-enabled devices might be appearing in our future.







Monday, November 14, 2011

Lasers can make brown eyes blue--but should they?

Gail Overton
Senior Editor
Laser Focus World

The daily news posting at entitled "Laser turns brown eyes blue" generated much discussion on LinkedIn. The comments weren't centered around how 'cool' or 'neat' the concept was, but instead focused on the technology details and the philosophical aspects of the procedure. After all, the LinkedIn audience to whom we share our Laser Focus World postings is not your average non-technical crowd; these are photonics industry professionals who are clearly concerned about how something works and what impact it has on society as a whole.

Turning brown eyes to blue may seem magical to a non-laser audience, but it is merely an extension of laser aesthetics--a topic profiled in our Photonics Applied feature series for November called "Looking good with lasers." Laser hair removal works on the principle of targeting melanin in the hair shaft and through laser heat, destroying the melanin and the hair follicle. Laser aesthetics also includes wrinkle removal, liposuction, and tattoo and lesion removal--different wavelengths of light attack different colored pigments in the tattoo or lesion, and it really works!

But even though lasers can turn brown eyes blue by targeting melanin, should they? One LinkedIn respondent said that they wished scientific research could be channeled into curing unsolved medical problems that we suffer rather than in trying to alter one's appearance for cosmetic reasons. I wholeheartedly agree; however, my sentiments will not change the fact that as long as people have "disposable incomes", money will be spent on luxuries. I was amazed to learn while researching the laser aesthetics article that teeth whitening is a $5.5 billion dollar global market, while the entire laser market is around $7 billion. Maybe we're all in the wrong business!

Still other LinkedIn comments focused on the technology. "Mankind has always sought to change his/her appearance--hair color, skin, and eyes," said Gennady Medvedkin. "Tomorrow we may witness artificial eyes made from silicon."

Medvedkin says that image sensors are really artificial eyes with great spatial resolution and color-sensing capabilities that can even exceed the capabilities of human vision. Thin silicon plates the size of the pupil could be implanted within the human body, completely replacing the eye, and recent computer algorithms allow extensions of the dynamic range in sensors up to 140 dB that are comparable to the human eye. Medvedkin says that the eye must adapt to very low light intensities for minutes and sometimes hours, whereas CMOS image sensors operate in the millisecond to second time range at low voltage with great success.

Personally, I'll keep my green eyes green and will be glad when this story fades from my memory; I'm getting tired of humming the "Don't it make my brown eyes blue" song from Crystal Gayle!