Zebra Stripes as Insect Defense

Researchers have found the vertical stripes of the zebra to be the least attractive hide pattern for horseflies (tabanids), who are otherwise attracted to horizontally polarized light to identify aquatic environments, suggesting the zebra stripes evolved as a defense against these insects.

Viking Navigational "Sunstones"

Researchers investigating Icelandic spar recovered from Viking shipwrecks have found the crystal separates polarized from unpolarized light, and these crystals may be the historical "sunstones" used to navigate even on cloudy days by locating the position of the hidden sun.

Channel-type Nanostructure Laser

Inspired by the structure of bright, iridescent bird feathers, researchers have constructed a new type of laser with a channel-type nanostructure that will allow them to self-assemble, making their fabrication easier, cheaper and faster.

Quaternary Rainbow Photo

The third- and fourth-order reflections (so-called tertiary and quaternary rainbows) have been captured on film for the first time, appearing after a storm in Kaempfelbach, Germany.

Renaissance Halo Diagram

Believed destroyed in World War II, a document by Jesuit scholar Christoph Scheiner has been rediscovered that records the "seven suns" optical halo effect that appeared over Rome in 1630, the earliest known documentation of that phenomenon.

First Images of Photoreceptors

Using a system of adaptive optics similar to that used by astronomers, scientists have directly imaged living photorecptors (rods and cones) on the back of the human eye for the first time, a technique that could lead to greater and more accurate diagnostic tools.

Moving Mirrors Create Light

Physicists have developed a method of drawing light from an empty vacuum by causing tiny superconducting mirrors to "wiggle" at around 5% the speed of light, collecting virtual photons into a light source and confirming a basic tenet of quantum mechanics.

Heart Paced with Laser

Researchers have found that pulsed laser light can pace the contractions in an embryonic avian heart with no apparent damage to tissue, which may lead to a new generation of pacemakers and neonatal devices.

Seeing Through Paint, Paper

Researchers have found a method to reconstruct the light passing through opaque objects such as paper, paint or biological tissue using a mathematical transmission matrix to reconstruct the image based on the known physical properties of the material, essentially viewing opaque solids as lenses.

Light Tied in Knots

Using specialized holograms to create and manipulate optical vortices, physicists were able to literally tie knots in beams of light using the science of knot theory, an abstract mathematics specialty that previously had no physical application.

New Microscopy Method Provides Increased Resolution

Scientists at the Howard Hughes Medical Institute's Janelia Farm Research Campus have developed a new method that produces the best three-dimensional resolution ever with an optical microscope.

Beginning with the super-high resolution photoactivated localization microscopy (PALM), researchers added an interferometry method to create what they call interferometric photoactivated localization microscopy (iPALM). iPALM provides resolution down to about 10 to 20 nanometers, or roughly ten times the size of an average protein molecule. The new method also allows a three-dimensional measurement of image depth, an attribute difficult to obtain with optical microscopes.

The science of interferometry uses a light beam reflected off a surface and then compared with its original beam. As it is reflected, the light undergoes a small shift in wavelength that can be detected and measured for incredibly small differences in depth and distance, such as on the surface of a computer chip. PALM extends the resolution for conventional optical microscopes, which are inherently limited by the wavelength of visible light, and iPALM can theoretically achieve resolutions on the subatomic scale.

iPALM uses a very modest amount of light, which is critical for some biological samples that could either be damaged by strong light or distorted by the need to use reflective dyes for optical measurements.

These results were published in the February 2nd issue of the Proceedings of the National Academy of Sciences.

Source: ScienceDaily

Spookfish Uses Mirrored Eyes to See

Scientists at Tuebingen University have discovered that the deep-sea spookfish is the first vertebrate to develop natural mirrors to focus light into its eyes.

Known for about 120 years, this first live specimen of the brownsnout spookfish (Dolichopteryx longipes) was caught last year off the coast of Tonga. Spookfish generally live at ocean depths of 1000 meters or more and in near total darkness. Their two compound eyes consist of two parts each, one of which is a mirrored surface used to focus faint traces of light into an image on the other part.

These mirrors are made up of guanine crystals, a naturally occurring substance in fish scales that produces a pearly, iridescent effect and has a high reflectivity. The mirrored portions are curved in such a way as to focus the reflected light on the fish's retina.

These results appear in a recent issue of Current Biology.

Photo: BBC News