Physics: Principles and Problems

 

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A New Kind of Glass
August 2003

You probably are familiar with liquid crystal technology. Many electronic devices such as laptop computers, digital watches, microwave ovens, and CD players contain a LCD (liquid crystal display). Liquid crystals are neither a liquid nor a solid. However, they are closer to a liquid than a solid. They are sensitive to temperature changes, especially heat. It takes quite a bit of heat to change a substance from a solid to a liquid crystal but only a little more heat to change that same liquid crystal into a real liquid. Another characteristic of liquid crystals is that they are affected by electric current.

Liquid crystal technology already has grown significantly since the discovery of liquid crystals in 1888. Scientists have spent a lot of time experimenting with liquid crystals to determine how they can be used in new technologies.

NASA has a research team, headed by David Weitz, working on a brand new application of liquid crystals. Liquid crystal droplets are being used to make panes of glass that can switch from transparent to diffracting and back again. When the glass pane is transparent, a laser beam can pass straight through it. When the glass pane is diffracting, it splits the beam, bending it in several directions. Basically, the glass pane can guide and manipulate beams of light. The change is caused by applying an electric field. Therefore, the pane could easily be controlled by the electric signals of a computer which would provide a new way to steer beams of light.

NASA's research team is investigating the possible applications of this new type of glass pane. One idea is to use the liquid crystal panes in reverse to combine beams of light from multiple telescopes. This could reduce the amount of glare from distant stars and allow scientists to search for distant planets that could be around the stars. Another possible application involves using the liquid crystal pane to "unwrinkle" light that has passed through Earth's atmosphere. If the technology works, it would provide a clear view of the solar system from Earth's surface.

Experiments are currently being conducted on Earth. But, Weitz hopes to design future experiments that could be conducted on the International Space Station.

Activity
Use the resources below to further investigate liquid crystals and how they are used. What is the overall structure of liquid crystals and how does that structure allow liquid crystals to manipulate light? Write a paragraph in your Science Journal that outlines other possible uses for liquid crystals.

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Physics: Principles and Problems