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| The term '''quantum defect''' is [[ambiguity|ambiguous]]. Various meanings are discussed below. Characteristic is that the defect deals with the loss on the smallest energy scale of light: that of the [[quantum]]. | | The individual who wrote the post is known as Jayson Hirano and he completely digs that title. To climb is some thing I truly appreciate performing. He is an info officer. For years she's been living in Kentucky but her husband wants them to transfer.<br><br>my weblog: online psychic ([http://www.khuplaza.com/dent/14869889 http://www.khuplaza.com]) |
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| ==Quantum defect in laser science==
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| In [[laser]] science, the term '''quantum defect''' refers to the fact that the energy of a pump photon is generally higher than that of a ''signal photon'' (photon of the output radiation). The difference of energies goes to the heat;
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| this heat may carry away the excess of [[entropy]] delivered with the multimode uncoherent pump.
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| The '''quantum defect''' of a [[laser]] can be defined as part of the energy of the pumping photon, which is lost (not turned into photons at the lasing wavelength) in the [[gain medium]] at the [[lasing]].<ref name="LaserQD">{{cite journal
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| | url=http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=6035&arnumber=234394&count=87&index=4
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| | author=T.Y.Fan
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| | coauthors=
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| | title=Heat generation in Nd:YAG and Yb:YAG
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| | journal=[[IEEE Journal of Quantum Electronics]]
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| | volume=29
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| | issue=6
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| | pages=1457–1459
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| | year=1993
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| | doi=10.1109/3.234394
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| | format=abstract
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| |bibcode = 1993IJQE...29.1457F }}</ref>
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| At given frequency <math>~\omega_{\rm p}~</math> of [[pump]] and given frequency <math>~\omega_{\rm s}~</math> of [[lasing]], the quantum defect <math>~q=\hbar\omega_{\rm p}-\hbar\omega_{\rm s}~</math>.
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| Such '''quantum defect''' has dimension of energy; for the efficient operation, the [[temperature]] of the [[gain medium]]
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| (measured in units of energy) should be small compared to the '''quantum defect'''.
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| <!--
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| Some colleagues define the '''quantum defect''' in a different way.
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| At given frequency <math>~\omega_{\rm p}~</math> of [[pump]] and given frequency <math>~\omega_{\rm s}~</math> of [[lasing]], the quantum defect <math>~q=1-\omega_{\rm s}/\omega_{\rm p}~</math>; according to this definition, '''quantum defect''' is dimensionless
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| .<ref> | |
| '''[[WHO HAD PUBLISHED A PAPER WITH SUCH DEFINITION??? Reference, please!!]]'''
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| </ref><br><br>
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| !-->
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| At a fixed pump frequency, the higher the quantum defect, the lower is the upper bound for the power efficiency.
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| ==Quantum defect in Rydberg atoms==
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| The '''quantum defect''' of a [[Rydberg atom]] refers to a correction applied to the equations governing Rydberg atom behavior to take into account the fact that the inner electrons do not entirely screen their associated charge in the nucleus.<ref>
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| http://www.phy.davidson.edu/StuHome/joesten/IntLab/final/rydberg.htm , | |
| Rydberg Atoms and the Quantum Defect at the site of [[Davidson College]], Physics department</ref> It is used particularly for the alkalis that contain a single electron in their outer shell.
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| The perfect 1/''r'' potential in the [[hydrogen atom]] leads to an [[electron]] [[binding energy]] given by
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|
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| :<math>E_\text{B} = -\dfrac{Rhc}{n^2}</math>,
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| where ''R'' is the [[Rydberg constant]], ''h'' is Planck's constant, ''c'' is the speed of light and ''n'' is the [[principal quantum number]].
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| For multi-electron atoms in Rydberg states with a low value of the [[angular momentum operator|orbital angular momentum]], there is a high probability of finding the excited electron near the nucleus where it can [[Polarizability|polarize]] or even penetrate the ion core, modifying the potential. The resulting shift of the energy levels is represented mathematically as an angular momentum dependent quantum defect, δ<sub>''l''</sub>:
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| :<math>E_\text{B} = -\dfrac{Rhc}{(n-\delta_l)^2}</math>.
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| The largest shifts occur when the orbital angular momentum is equal to 0 (normally labelled 's') and these are shown in the table for the [[alkali metals]]:<ref>C.J.Foot, Atomic Physics, Oxford University Press, ISBN 978-0-19-850695-9</ref>
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| {| class="wikitable"
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| |-
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| ! Element !! Configuration !! n* !! δ<sub>''s''</sub>
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| |-
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| | Li || 2s || 1.59 || 0.41
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| |-
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| | Na || 3s || 1.63 || 1.37
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| |-
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| | K || 4s || 1.77 || 2.23
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| |-
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| | Rb || 5s || 1.81 || 3.19
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| |-
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| | Cs || 6s || 1.87 || 4.13
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| |}
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| ==See also==
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| *[[External quantum efficiency]]
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| *[[Quantum efficiency of a solar cell]]
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| ==References==
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| <references/>
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| <!-- {{disambig}} recover this as soon as we have separate articles for each of meanings mentioned
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| !-->
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| [[Category:Atoms]]
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| [[Category:Laser science]]
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| {{quantum-stub}}
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The individual who wrote the post is known as Jayson Hirano and he completely digs that title. To climb is some thing I truly appreciate performing. He is an info officer. For years she's been living in Kentucky but her husband wants them to transfer.
my weblog: online psychic (http://www.khuplaza.com)