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Polarized Light Emitting Diode

Chances are you own or regularly use at least one device that employs light emitting diodes, or LEDs, which in recent years have become commonplace as light sources for liquid crystal displays (LCDs) in everything from cell phones to laptop computers.

Thanks to work done by scientist Martin Schubert, LEDs are set to become even more effective and efficient, and poised for use in an even greater variety of products. Schubert developed a version of LED that capitalizes on polarized light, or light that travels in a single plane, which makes it possible to better control the light, waste less of it, and point more of it toward its target location. His polarized LED emits super-focused light that has the ability to produce more crisp, colorful and lifelike images than ever before, even with traditional LEDs. To boot, his invention helps make LEDs more energy-efficient, increasing both their power and environmental soundness.

Schubert was born in Germany and raised in New Jersey and later the Boston area. He was inspired early on by some dedicated high school math and science teachers to pursue a career in engineering. He received his bachelorís from Cornell University in 2004 and masterís in 2005, both in electrical engineering, and was set to pursue a career in computer chip development. However his father, renowned lighting research expert and senior chair of the Rensselaer Future Chips Constellation, E. Fred Schubert, recognized his sonís skills and ideas for the advancement of lighting technology and recruited him to join the large lighting research effort at Rensselaer Polytechnic Institute in Troy, New York.

Schubert began working toward his doctoral degree in electrical, computer, and systems engineering at RPI while working with his fatherís team. As soon as he arrived at the school, he jumped right into independent research under the guidance of his adviser, Michael Shur, the Patricia W. and C. Sheldon Roberts í48 Professor of Solid State Electronics and director of the Rensselaer/IBM Center for Broadband Data Transfer Science and Technology.

Schubert first discovered that traditional LEDs actually produce polarized light, but existing LEDs did not capitalize on the lightís polarization. Armed with this information, he devised an optics setup around the LED chip to enhance the polarization, creating the first polarized LED. He hopes his device will soon be used to replace widely used fluorescent lights that are less efficient and laden with mercury. His innovation also could be used for street lighting, high-contrast imaging, sensing, and free-space optics, he said.

During his time with Rensselaer Schubert has published three peer-reviewed, archival papers and filed for several patents related to his polarized LEDs. He is also co-author of 15 other papers on related research, including a paper in one of the top journals in his field, ďNature Photonics.Ē

For his efforts, Schubert was awarded the $30,000 Lemelson-Rensselaer Student Prize in 2008. After graduation from RPI that year, he plans to pursue a career in semiconductor devices and photonics.

[April 2008]

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