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Doppler cooling. Simplified principle of Doppler laser cooling: 1. A stationary atom sees the laser neither red- nor blue-shifted and does not absorb the photon. 2. An atom moving away from the laser sees it red-shifted and does not absorb the photon. 3.1. An atom moving towards the laser sees it blue-shifted and absorbs the photon, slowing the ...
Polarization gradient cooling (PG cooling) is a technique in laser cooling of atoms. It was proposed to explain the experimental observation of cooling below the doppler limit. [1] Shortly after the theory was introduced experiments were performed that verified the theoretical predictions. [2] While Doppler cooling allows atoms to be cooled to ...
Sub-Doppler cooling is a class of laser cooling techniques that reduce the temperature of atoms and molecules below the Doppler cooling limit. In experiment implementation, Doppler cooling is limited by the broad natural linewidth of the lasers used in cooling. [ 1] Regardless of the transition used, however, Doppler cooling processes have an ...
The Doppler effect (also Doppler shift) is the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave. [1][2][3] The Doppler effect is named after the physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a ...
AN/APG-63. The AN/APG-63 and AN/APG-70 are a family of all-weather multimode radar systems designed by Hughes Aircraft (later Raytheon) for the F-15 Eagle air superiority fighter. These X band pulse-Doppler radar systems are designed for both air-air and air-ground missions; they are able to look up at high-flying targets and down at low-flying ...
Resolved sideband cooling. Resolved sideband cooling is a laser cooling technique allowing cooling of tightly bound atoms and ions beyond the Doppler cooling limit, potentially to their motional ground state. Aside from the curiosity of having a particle at zero point energy, such preparation of a particle in a definite state with high ...
Gray molasses. Gray molasses is a method of sub-Doppler laser cooling of atoms. It employs principles from Sisyphus cooling in conjunction with a so-called "dark" state whose transition to the excited state is not addressed by the resonant lasers. Ultracold atomic physics experiments on atomic species with poorly-resolved hyperfine structure ...
A particular case is the thermal Doppler broadening due to the thermal motion of the particles. Then, the broadening depends only on the frequency of the spectral line, the mass of the emitting particles, and their temperature , and therefore can be used for inferring the temperature of an emitting (or absorbing) body being spectroscopically ...