New Approach Can Change the Extent to Which Optical Devices Scatter Light

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In holographic displays, cells filled with a mixture of electrically responsive solid materials and a fluid could change their diffusivity when charged by an electrode, in much the way that cells filled with ionized gas change their color in plasma TVs. Adjacent cells could thus steer light in slightly different directions, mimicking the reflection of light off of a contoured surface and producing the illusion of three-dimensionality.

Liquid-solid mixtures could also be used to produce tunable diffraction gratings, which are used in some sensing applications to filter out light or other electromagnetic radiation of particular frequencies, or in tunable light diffusers of the sort photographers use to make the strongly directional light of a flash feel more like ambient light.

The computer model that the researchers describe in their paper predicts the diffusivity of a liquid-solid mixture on the basis of the physical characteristics of the solid particles — how jagged or spiky they are — and on their concentration in the liquid. That model, Heshmat says, could be used to develop solid particles tailored to specific applications.

The appeal of this method may even reach beyond science and engineering. “I understand the obvious potential scientific applications listed in the abstract,” says Aydogan Ozcan, a professor of electrical engineering at the University of California at Los Angeles. “But I think this kind of approach could potentially be useful for designing new artwork — for interior design, for example. You can design furniture parts or artwork that will change the light-matter interaction and visual perception on demand or through a programmed interface, which would bring dynamic light effects indoors. Similarly, it can be used in architectural designs to replace curtains by structured interfaces.”