Over eight decades ago, in 1925, Albert Einstein predicted the eventual creation of the atom laser. However, up until now, no one could actually build one, because no one could find a way to stop atoms from bouncing into one another. For that reason, it has been considered a practical impossibility. However, the “impossible” has been achieved by a team of Italian scientists who have managed to create the world’s first atomic laser.
Lasers, as they exist now, are concentrated streams of light particles, or photons. “Laser” is an acronym for "light amplification by stimulated emission of radiation". Lasers are possible because of the way light interacts with electrons and the beam consists entirely of photons, released by electrons as excess energy, when they drop from an outer to an inner level.
The discovery by Florence University researchers will produce lasers of atoms, rather than photons, reported the Italian news agency ANSA recently.
Inguscio's team used potassium isotopes to build an "atomic condensate" squeezed into a harmonious whole by a magnetic field, similar to a theoretical model envisioned by Einstein and his colleague Satyendra Nath Bose, Inguscio said. "In this way the interaction of atoms is virtually nonexistent."
An atomic laser is eagerly awaited in the field of micro-electronics, says Inguscio. As the technology is so new, the many possibilities of the new technology are still being explored.
A a of recent laser history: a regular photon "lunar laser ranging retroreflector array was placed on the moon by Apollo 11 astronauts Buzz Aldrin and Neil Armstrong put it there on July 21, 1969, about an hour before the end of their final moonwalk. Almost 40 years later, it's the only Apollo science experiment still running. Using these mirrors astronomers can 'ping' the moon with laser pulses from telescopes and pinpoints the Earth-moon distance with awesome precision.
A key observing site is the McDonald Observatory in Texas where a 0.7 meter telescope regularly pings reflectors in the Sea of Tranquility (Apollo 11), at Fra Mauro (Apollo 14) and Hadley Rille (Apollo 15), and, sometimes, in the Sea of Serenity.
Over the decades, researchers using lasers have carefully traced the moon's orbit, and they've learned that:
The moon is spiraling away from Earth at a rate of 3.8 cm per year, due to Earth's ocean tides; the moon probably has a liquid core; Newton's gravitational constant G is stable, changing less than 1 part in 100-billion since the laser experiments began.
Laser results have also been used to to check Einstein's theory of gravity, the general theory of relativity and have found that Einstein's equations predict the shape of the moon's orbit as well as laser ranging can measure it.
Posted by Rebecca Sato with Casey Kazan.