High-brightness polarized light-emitting diodes

Researchers have designed a light-emitting diode (LED) that produces bright directional polarized blue light. The device, developed at the University of California at Santa Barbara in the USA by Elison Matioli and collaborators, is based on a variant of the semiconductor gallium nitride, grown on a specifically crystal direction that yields emission of polarized light. The researchers improved light extraction from the device by drilling aligned arrays of holes at precisely defined intervals into the substrate. This photonic crystal structure selectively enhances the emission of polarized light for particular emission angles by up to a factor of 1.8. High-brightness LEDs emitting polarized light are of interest for flat-screen displays, and also for household lighting because they minimize the glare from light reflections.

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