Tag Archives: optics

Scriths and legends: hidden portals a possibility

hiddenResearchers in Hong Kong are developing technologies that could one day lead to hidden portals [1]:

In the research paper, the researchers from the Hong Kong University of Science and Technology and Fudan University in Shanghai describe the concept of a “a gateway that can block electromagnetic waves but that allows the passage of other entities”

The gateway, which is now much closer to reality, uses transformation optics and an amplified scattering effect from an arrangement of ferrite materials called single-crystal yttrium-iron-garnet that force light and other forms of electromagnetic radiation in complicated directions to create a hidden portal.

Previous attempts at an electromagnetic gateway were hindered by their narrow bandwidth, only capturing a small range of visible light or other forms of electromagnetic radiation. This new configuration of metamaterials however can be manipulated to have optimum permittivity and permeability – able to insulate the electromagnetic field that encounters it with an appropriate magnetic reaction.

Whilst I’m not entirely sure how this metamaterial in supposed to behave, or what is meant by “other entities” in this context, such a substance has overtones of the Ringworld construction material described in Larry Niven‘s Ringworld series, which IIRC was impermeable to 40% of neutrino emissions, and under the application of a particular instrument would allow people to walk through it.

[1]: The article is somewhat vague on how exactly this portal will work in reality, but I gather that it works either like a perfected “holographic mirror” that you can walk through, or else simply a glass-like sheet that can become reflective when required to. In any case

[from h+ Magazine][image from fdecomite on flickr]

Light in a bottle

microresonatorScientists have developed a technique for confining light within a bottle:

Similar to the motion of a charged particle stored in a magnetic bottle, i.e., a particular spatially varying magnetic field, the light oscillates back and forth along the fiber between two turning points. For this reason, this novel type of microresonator realized by the physicists in Mainz is referred to as a bottle resonator. Tuning the bottle resonator to a specific optical frequency can be accomplished by simply pulling both ends of the supporting glass fiber. The resulting mechanical tension changes the refractive index of the glass, so that depending on the tension, the round-trip of the light is lengthened or shortened.

This could lead to the creation of a glass fibre quantum interface between light and matter, which in turn is an important component of hypothetical quantum computers and quantum communication systems.

[from Physorg][image from Physorg]

Behold – the magic cloak of illusion! Er… it was here a minute ago…

vanishing actA big part of the fun of this blogging gig (for me at least) is watching stories resurface and reiterate themselves over time. Point in case: metamaterials and ‘invisibility cloaks’, which cropped up a few times last year, and which raise their head again with news from Hong Kong University that researchers have discovered a theoretical method for not only making things appear invisible, but also for making one thing appear to be another thing entirely. Confused? Well, this might help:

The trick is to create a material in which the permittivity and permeability are complementary to the values in a nearby region of space containing the mouse we want to hide. “Complementary” means that the material cancels out the effect that the mouse has on a plane lightwave passing through. So a plane wave would be bent by the mouse but then bent back into a plane as it passes through the complementary material, making the mouse disappear.

The second step is to then distort this plane wave in the way that an elephant would. This means creating transformational material that distorts a plane lightwave in the same way as an elephant. So anybody looking at this mouse would instead see an elephant.

An invisibility cloak is just a special case of this, when the mouse is simply replaced by the illusion of free space, say Chan and co.

Simply? Well, they sound pretty sure of themselves, but I’ll maintain my skepticism until I see it actually working… or don’t see it, rather. [via SlashDot; image by crystalchu]

‘Beetlepunk’ – biomimicry and the photonic weevil

Lamprocyphus augustus - photonic weevilWith designers and engineers increasingly turning to the natural world for inspiration, biomimicry is an increasingly important part of the sciences. Author Janine Beynus offers an outline of the discipline’s key principles;

The core idea is that nature, imaginative by necessity, has already solved many of the problems we are grappling with. Animals, plants, and microbes are the consummate engineers. They have found what works, what is appropriate, and most important, what lasts here on Earth. This is the real news of biomimicry: After 3.8 billion years of research and development, failures are fossils, and what surrounds us is the secret to survival.

Like the viceroy butterfly imitating the monarch, we humans are imitating the best adapted organisms in our habitat. We are learning, for instance, how to harness energy like a leaf, grow food like a prairie, build ceramics like an abalone, self-medicate like a chimp, create color like a peacock, compute like a cell, and run a business like a hickory forest.

As an real-world illustration of biomimetic principles, this morning, Wired‘s Brandon Keim presented a design problem from the field of optical computing;

For decades, scientists have dreamed of computer chips that manipulate light rather than electricity. Unlike electrons, photons can cross paths without interfering with each other, so optical chips could compute in three dimensions rather than two, crunching data in seconds that now takes weeks to process.

For now, though, optical computing remains a dream. The chips require crystals that channel photons as nimbly as silicon channels electrons — and though engineers have been able to imagine the ideal photonic crystal, they’ve been unable to build it.

Earlier this month, a team of American material scientists found a biomimetic solution in the body of Lamprocyphus augustus – a Brazilian weevil. According to the research,

the inch-long Brazilian beetle’s iridescent green scales are composed of chitin arranged by evolution in precisely the molecular configuration that has confounded the would-be fabricators of optical computers.

The “scales’ molecular arrangement, which had the same pattern as the atoms of carbon in a diamond.” So, with real diamonds too dense for the task, and artificial diamonds taking months to construct, the L. augustus scales offer a quick and easy solution.

Of course – as co-author Michael Bartl notes – optical computers won’t use actual weevil scales. The plan is to use the scales as a mould, replacing the chitin with something more suitable for the industrial context.

For someone approaching the issue from a science fictional standpoint, this sent my mind careering down a whole new avenue of speculation. Imagine a world in which Bartl’s mould plan is ineffective. Here, much of the high-end computing infrastructure is entirely dependent on this tiny Brazilian insect.

Our protagonists are rogue entomologists, forced to balance the “bug bounties” offered by the military-industrial complex with the ‘pure’ research of their underfunded university departments. Academic soul-searching, Brazilian protesters, university politics, intellectual property wrangles, and a left-wing subtext. It’s got it all.

I call it ‘Beetlepunk’. 😀

Finally, if this whole ‘biomimicry’ thing strikes you as interesting, be sure to check out Janine Beynus’ presentation from TED 2005. She’s a skilled orator, and her TED talk is a really good way of getting your head around the subject.

[Image by Barbara Strnadova at God of Insects]

Scientists create dynamic holographic display

3ddisp_hol Scientists from the University of Arizona have figure out how to make holographic displays, viewable without special eyeware, that can be erased and rewritten in a matter of minutes. (Via PhysOrg.)

Dynamic hologram displays could be made into devices that help surgeons track progress during lengthy and complex brain surgeries, show airline or fighter pilots any hazards within their entire surrounding airspace, or give emergency response teams nearly real-time views of fast-changing flood situations or traffic problems, for example…and no one yet knows where the advertising and entertainment industries will go with possible applications…

The prototype display is only four inches by four inches and only comes in red, but larger displays in full colour are considered possible. The researchers are aiming for a one-foot-by-one-foot display next, then a three-foot-by-three-foot display. Eventually they hope to be able to display life-sized holographic images of humans that can be updated every few minutes.

Watch a video here.

The researchers point out that a great deal of data is lost when three-dimensional information, such as that collected by an MRI or CAT scan, is displayed in two dimensions on a flat computer monitor. As they say, “…when we develop larger, full-color 3-D holograms, every hospital in the world will want one.”

And two minutes after the first one is installed, hospital staff will be referring to the room it’s placed in as the “holodeck.”

(Image: University of Arizona.)