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The MOT cloud is loaded from a background of thermal vapour, or from an atomic beam, usually slowed down to the capture velocity using a Zeeman slower. However, the trapping potential in a magneto-optical trap is small in comparison to thermal energies of atoms and most collisions between trapped atoms and the background gas supply enough ...
Optical molasses schematic. Optical molasses is a laser cooling technique that can cool neutral atoms to as low as a few microkelvin, depending on the atomic species. An optical molasses consists of 3 pairs of counter-propagating orthogonally polarized laser beams intersecting in the region where the atoms are present.
They produce a well controlled continuous beam spanning up to 100 ms, whereas their predecessor produced only short pulses of atoms. However, this does not constitute a continuous atom laser since the replenishing of the depleted BEC lasts approximately 100 times longer than the duration of the emission itself (i.e. the duty cycle is 1/100).
A photograph showing two Fulton MX-991/U Flashlights, next to an unofficial reproduction and a standard angle-head flashlight. The MX-991/U Flashlight (aka GI Flashlight, Army flashlight, or Moonbeam [1]) from the TL-122 military flashlight series of 1937-1944 and is a development of the MX-99/U flashlight issued in 1963 [clarification needed].
The beam of a single transverse mode (gaussian beam) laser eventually diverges at an angle that varies inversely with the beam diameter, as required by diffraction theory. Thus, the "pencil beam" directly generated by a common helium–neon laser would spread out to a size of perhaps 500 kilometers when shone on the Moon (from the distance of ...
In the rest frame of the atoms with velocity, , in the atomic beam, the frequency of the laser beam is shifted by . In the presence of a magnetic field B {\displaystyle B} , the atomic transition is Zeeman shifted by an amount μ ′ B / ℏ {\displaystyle \mu 'B/\hbar } (where μ ′ {\displaystyle \mu '} is the magnetic moment of the transition).
For example, if laser light illuminates a warm cloud of atoms from all directions and the laser's frequency is tuned below an atomic resonance, the atoms will be cooled. This common type of laser cooling relies on the Doppler effect where individual atoms will preferentially absorb laser light from the direction opposite to the atom's motion.
Atomic beam is special case of particle beam; it is the collimated flux (beam) of neutral atoms. The imaging systems using the slow atomic beams can use the Fresnel zone plate (Fresnel diffraction lens) of a Fresnel diffraction mirror as focusing element. The imaging system with atomic beam could provide the sub-micrometre resolution.