Researchers have developed innovative flat, optical lenses as part of a collaboration between NASA's Jet Propulsion Laboratory and the California Institute of Technology, both in Pasadena, California. These optical components are capable of manipulating light in ways that are difficult or impossible to achieve with conventional optical devices.
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Seen under a scanning electron microscope, the new metasurfaces that the researchers created resemble a cut forest where only the stumps remain. Each silicon stump, or pillar, has an elliptical cross section, and by carefully varying the diameters of each pillar and rotating them around their axes, the scientists were able to simultaneously manipulate the phase and polarization of passing light.Phase has to do with the separation between peaks of light waves; light waves in phase with each other combine to produce a single, more powerful wave. Manipulating its phase influences the degree to which a light ray bends, which in turn influences whether an image is in or out of focus. Polarization refers to the way some light waves vibrate only in a particular direction, whereas waves in natural sunlight vibrate in all directions. Manipulating the polarization of light is essential for the operation of advanced microscopes, cameras and displays; the control of polarization also enables simple gadgets such as 3-D glasses and polarized sunglasses.
Metamaterials promise a wide range of applications from better solar cells and sensors to invisibility cloaks.
(Score: 2) by Runaway1956 on Saturday September 05 2015, @02:13AM
They're printing this onto silicone chips - then they alter the diameter of those "stumps"? Rotating them seems easy enough, but altering the diameter of they physical rods is done, how? The NASA release isn't any more informative - http://www.jpl.nasa.gov/news/news.php?feature=4706 [nasa.gov]
A wild guess is, they alter an electric current passing through the lens, but nanotechnology ain't exactly macrotech.
(Score: 2, Informative) by soybp on Saturday September 05 2015, @06:10PM
The precise arrangement of the nanostructure etched into the silicon chip allows the electric field to be varied slightly at each air/Si interface, allowing for a slight reorientation of the vector at each interface. Since the overall chip has many interfaces, the location of each nanopillar has a slight effect on the total output and taken together, the output waveform is transformed significantly vs. the input waveform. The pillar locations were chosen by computer algorithm by solving Maxwell's equations (sometimes just the Helmholtz wave equation) to achieve a desired output waveform. An example freeware program to investigate such effects is Modesolver: http://www.photonics.umd.edu/software/wgmodes/ [umd.edu] . You can read more about making silicon photonic crystals here: http://www.helios-project.eu/Download/Silicon-photonics-course/Ch5-Resonant-structures [helios-project.eu] (apparently a ~slow download, but works).
To answer your question, the featured chip is a static design, it does not change over time. The output is of fixed composition once the chip is etched.
I didn't read the article, but note that silicon is an infrared photonic material, and does not pass light in the visible range. As such the featured chip likely functions in the IR band only.