AsianScientist (Jun. 28, 2011) – The eye of the peacock mantis shrimp has inspired an international team of researchers to develop a two-part waveplate that could improve CD, DVD, blu-ray and holographic technology, creating even higher definition and larger storage density.
Peacock mantis shrimp can see circularly polarized light – like the light used to create 3-D movies. Some researchers believe the mantis shrimp’s eyes are better over the entire visual spectrum than any man-made waveplates.
A waveplate is a transparent slab that can alter the polarization of light because it uses birefringent materials like the mineral calcite. This print viewed through a calcite lens appears as doubled and slightly offset letters. In some cases, to create the range and transparency required, two different materials are stacked or joined, but this type of construction sometimes delaminates, coming apart at the seams.
“We want to change the polarization without affecting the amount of light that gets through,” said Akhlesh Lakhtakia, Charles Godfrey Binder Professor of Engineering Science and Mechanics, Penn State. “We want both transmittance and changing polarization to occur quite independent of frequency. In other words, we do not want to affect the color.”
Together with a team of engineers from the National Taipei University of Technology, Lakhtakia developed a method to produce periodically multilayered materials, similar to the lens in the peacock mantis shrimp. The researchers report their work in the current online issue of Nature Communications.
The research team’s waveplate is made of two layers of nanorods that are structurally similar to those in the eye of the peacock mantis shrimp. They begin with tantalum pentoxide, but deposit the two layers using different deposition processes creating a multilayered thin film.
One method produces a layer of needle-like nanorods that are all parallel to each other and slanted in the same direction. The second method produces nanorods that are also parallel to each other but are upright. Because of the two materials, the waveplate can polarize or repolarize light over the visual spectrum.
“The two separate layers are needed so that we can play off one against the other to achieve the desired polarization without significantly reducing transmittance over a broad range of frequencies,” said Lakhtakia.
The article can be found at: Jen YJ et al. (2011) Biologically inspired achromatic waveplates for visible light.
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Source: Penn State.
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