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The Doppler temperature is the minimum temperature achievable with Doppler cooling. When a photon is absorbed by an atom counter-propagating to the light source, its velocity is decreased by momentum conservation. When the absorbed photon is spontaneously emitted by the excited atom, the atom receives a momentum kick in a random direction.
In astronomy and plasma physics, the thermal Doppler broadening is one of the explanations for the broadening of spectral lines, and as such gives an indication for the temperature of observed material. Other causes of velocity distributions may exist, though, for example, due to turbulent motion. For a fully developed turbulence, the resulting ...
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 ...
The equations for the use of the data retrieved from these tables are very simple. Q= heat gain, usually heat gain per unit time. A= surface area. U= Overall heat transfer coefficient. CLTD= cooling load temperature difference. SCL= solar cooling load factor. CLF= cooling load factor. SC= shading coefficient.
Saturated absorption spectroscopy measures the transition frequency of an atom or molecule between its ground state and an excited state. In saturated absorption spectroscopy, two counter-propagating, overlapped laser beams are sent through a sample of atomic gas. One of the beams stimulates photon emission in excited atoms or molecules when ...
Of the two ħk kicks the atom receives in each cooling cycle, the first cools, and the second heats: a simple description of laser cooling which enables us to calculate a point at which these two effects reach equilibrium, and therefore define a lower temperature limit, known as the Doppler cooling limit.
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 ...
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