March 1994

The Allure of Liquid Crystal Displays

Steven E. Shields

Nearly everyone has seen liquid crystal displays (LCDs). They include both the inexpensive devices used in watches and sophisticated displays designed for use as computer screens. Some LCDs are even capable of projecting video images onto screens 20 m wide and more. Yet LCD technology is a relatively recent development.

Femtosecond Lasers: The Next Generation

For over a decade now, femtosecond lasers have helped us to understand processes relevant to both basic and applied science, including chemical reactions, melting, photosynthesis, vision, and semiconductor physics. More recently, technological applications for short optical pulses, such as fiber optic communications, have developed.

Hubble Rescue Mission: A Stellar Success

On the eve of the New Year, NASA scientists got the best news they'd received in a long time. Images sent back from the newly serviced Hubble Space Telescope (HST) confirmed that the world's first orbiting telescope would fulfill its mission to probe the universe with unprecedented clarity and sensitivity. "The image of galaxy M100 clearly showed that we'd fixed Hubble," says HST project scientist Ed Weiler. "Because we can see individual stars in this galaxy, we will be able to measure the Hubble constant and, thus, the age of the universe."

Arrays Of Vertical Cavity Surface-Emitting Lasers Go Commercial

New vertical cavity surface-emitting lasers (VCSELs) solve many of the problems that plague edge-emitting lasers by making a simple, but revolutionary, "right turn" to allow light emission perpendicular to the semiconductor wafer surface. VCSELs are patterned using standard integrated circuit fabrication techniques and "vertically" emit round low-divergence light beams.


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