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Laser Cooling and Atomic Physics

    PAST:   None
    PRESENT: Ongoing Research
    FUTURE: BECEDM-XPARCS RACE SALSMW-G

Launch Date: Proposed.
Mission Duration: One year

 

SAL image

New technologies have emerged in the last few years that may prove significant in the future. These technologies are based on quantum mechanics, the fundamental laws that determine how very small objects such as atoms and subatomic particles behave. One of the most promising of these new technologies is the atom laser, a source of coherent matter waves, that is similar to the conventional laser, which is a source of coherent light waves. The Space Atom Laser (SAL) is an experiment proposed for a possible future flight in space, that will study the physics of these novel devices. SAL will also use an atom laser to perform studies in atomic optics, a field which attempts to manipulate beams of atoms in ways similar to how conventional optics are used to manipulate beams of light. In this specialized field, atom opticians study how to make lenses, mirrors, beam splitters and interferometers for atomic beams.

Quantum mechanics states that all objects have both a wave nature and a particle nature. At colder temperatures, the wave nature becomes more evident. An atom laser works by cooling a trapped dilute gas of atoms to a temperature so cold that the atomic waves overlap. For certain types of atoms, the gas will undergo a transition such that almost all the atoms are in the exact same state, with the same wavelength. A few atoms are allowed to leak out of the trap, forming the output of the atom laser. This output shares many characteristics with a laser beam: its bright (there are a lot of atoms in the same state), its collimated (the atoms all go in one direction, and don't spread out), and it is coherent (the phase of the atom waves are all the same, so that is the troughs and crests of the wave are all aligned). There are differences however-the atoms move extremely slowly, and they have mass, so they fall in gravity (gravity affects light as well, but by an amount that is usually too small to notice.)

Simple atom lasers have been demonstrated in several of the leading labs around the world. It has been predicted that they will have a variety of uses, ranging from advanced atomic gyroscopes, to lithography, where they might be used to produce advanced microchips. However, many of these applications are hampered by the fact that atom lasers are so sensitive to gravity. It is predicted that in the microgravity of space the atomic beam created with an atom laser will propagate like a true laser beam, allowing some of these technological applications to be proven.



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