Related topics: light · laser · electrons · molecules · atoms

Better than holograms: A new 3-D projection into thin air

One of the enduring sci-fi moments of the big screen—R2-D2 beaming a 3-D image of Princess Leia into thin air in "Star Wars"—is closer to reality thanks to the smallest of screens: dust-like particles.

Smart atomic cloud solves Heisenberg's observation problem

Scientists at the University of Copenhagen have developed a hands-on answer to a challenge linked to Heisenberg's Uncertainty Principle. The researchers used laser light to link caesium atoms and a vibrating membrane. The ...

The amazing camera that can see around corners (w/ video)

How can a person see around a blind corner? One answer is to develop X-ray vision. A more mundane approach is to use a mirror. But if neither are an option, a group of scientists led by Genevieve Gariepy have developed a ...

Physicists discover 'smoke rings' made of laser light

Most basic physics textbooks describe laser light in fairly simple terms: a beam travels directly from one point to another and, unless it strikes a mirror or other reflective surface, will continue traveling along an arrow-straight ...

Accelerating light beams in curved space

By shining a laser along the inside shell of an incandescent light bulb, physicists have performed the first experimental demonstration of an accelerating light beam in curved space. Rather than moving along a geodesic trajectory ...

How does an experiment at LIGO actually work?

Gravitational waves are mysterious ripples in the fabric of space and time that travel across our universe at the speed of light. Predicted by Einstein exactly 100 years ago, a number of experiments have been searching for ...

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Laser

A laser is a device that emits light (electromagnetic radiation) through a process called stimulated emission. The term laser is an acronym for light amplification by stimulated emission of radiation. Laser light is usually spatially coherent, which means that the light either is emitted in a narrow, low-divergence beam, or can be converted into one with the help of optical components such as lenses. Typically, lasers are thought of as emitting light with a narrow wavelength spectrum ("monochromatic" light). This is not true of all lasers, however: some emit light with a broad spectrum, while others emit light at multiple distinct wavelengths simultaneously. The coherence of typical laser emission is distinctive. Most other light sources emit incoherent light, which has a phase that varies randomly with time and position.

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