Hanle effect
TheHanle effect,[1]also known aszero-field level crossing,[2]is a reduction in the polarization of light when the atoms emitting the light are subject to a magnetic field in a particular direction, and when they have themselves been excited by polarized light.
Experiments which utilize the Hanle effect include measuring the lifetime ofexcited states,[3]and detecting the presence of magnetic fields.[4]
History
[edit]The first experimental evidence for the effect came fromRobert W. Wood,[5][6]andLord Rayleigh.[7]The effect is named afterWilhelm Hanle,who was the first to explain the effect, in terms ofclassical physics,inZeitschrift für Physikin 1924.[8][9]Initially, the causes of the effect were controversial, and many theorists mistakenly thought it was a version of theFaraday effect.Attempts to understand the phenomenon were important in the subsequent development ofquantum physics.[10]
An early theoretical treatment of level crossing effect was given byGregory Breit.[11]
Applications
[edit]Observation of the Hanle effect on the light emitted by the Sun is used to indirectly measure the magnetic fields within the Sun, see:
The effect was initially considered in the context of gasses, followed by applications tosolid state physics.[12]It has been used to measure both the states of localized electrons[13]andfree electrons.[14]Forspin-polarizedelectrical currents, the Hanle effect provides a way to measure the effective spin lifetime in a particular device.[15]
Related effects
[edit]The zero-field Hanle level crossings involve magnetic fields, in which the states which are degenerate at zero magnetic field are split due to theZeeman effect.There is also the closely analogous zero-field Stark level crossings with electric fields, in which the states which are degenerate at zero electric field are split due to theStark effect.Tests of zero field Stark level crossings came after the Hanle-type measurements, and are generally less common, due to the increased complexity of the experiments.[16]
See also
[edit]References
[edit]- ^Kastler, Alfred(1974)."50 Jahre Hanle-Effekt: Rückblick und Vorblick"[50 year Hanle Effect: Review and Prospects].Physik Journal(in German).30(9): 394–404.doi:10.1002/phbl.19740300903.ISSN0031-9279.
- ^Lurio, Allen; deZafra, R. L.; Goshen, Robert J. (1964-06-01). "Lifetime of the First1P1State of Zinc, Calcium, and Strontium ".Physical Review.134(5A): A1198–A1203.Bibcode:1964PhRv..134.1198L.doi:10.1103/physrev.134.a1198.ISSN0031-899X.
- ^Zimmermann, Dieter (1975). "Determination of the lifetime of the 4p1/2-state of potassium by Hanle-effect ".Zeitschrift für Physik A.275(1): 5–10.Bibcode:1975ZPhyA.275....5Z.doi:10.1007/bf01409492.ISSN0340-2193.S2CID119987034.
- ^Dupont-Roc, J.;Haroche, S.;Cohen-Tannoudji, C.(1969). "Detection of very weak magnetic fields (10−9gauss) by87Rb zero-field level crossing resonances ".Physics Letters A.28(9): 638–639.Bibcode:1969PhLA...28..638D.doi:10.1016/0375-9601(69)90480-0.ISSN0375-9601.
- ^Wood, R.W.(1912)."LXVII. Selective reflexion, scattering and absorption by resonating gas molecules".The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science.23(137): 689–714.doi:10.1080/14786440508637267.ISSN1941-5982.
- ^Wood, R. W.;Ellett, A. (1923-06-01)."On the Influence of Magnetic Fields on the Polarisation of Resonance Radiation".Proceedings of the Royal Society A.103(722): 396–403.Bibcode:1923RSPSA.103..396W.doi:10.1098/rspa.1923.0065.ISSN1364-5021.
- ^Rayleigh, L.(1922-11-01)."Polarisation of the Light Scattered by Mercury Vapour Near the Resonance Periodicity".Proceedings of the Royal Society A.102(715): 190–196.Bibcode:1922RSPSA.102..190R.doi:10.1098/rspa.1922.0080.ISSN1364-5021.
- ^Hanle, Wilhelm(1924-12-01). "Über magnetische Beeinflussung der Polarisation der Resonanzfluoreszenz".Zeitschrift für Physik(in German).30(1): 93–105.Bibcode:1924ZPhy...30...93H.doi:10.1007/bf01331827.ISSN0044-3328.S2CID120528168.
- ^Hanle, W.(1925). "Die magnetische Beeinflussung der Resonanzfluoreszenz".Ergebnisse der Exakten Naturwissenschaften(in German). Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 214–232.doi:10.1007/978-3-642-94259-4_7.ISBN978-3-642-93859-7.
- ^J Alnis; K Blushs; M Auzinsh; S Kennedy; N Shafer-Ray; E R I Abraham (2003)."The Hanle effect and level crossing spectroscopy in Rb vapour under strong laser excitation"(PDF).Journal of Physics B.36(6): 1161–1173.Bibcode:2003JPhB...36.1161A.doi:10.1088/0953-4075/36/6/307.S2CID250734473.Archived fromthe original(PDF)on 2016-03-03.Retrieved2012-03-06.
- ^Breit, G.(1933-04-01). "Quantum Theory of Dispersion (Continued). Parts VI and VII".Reviews of Modern Physics.5(2): 91–140.Bibcode:1933RvMP....5...91B.doi:10.1103/revmodphys.5.91.ISSN0034-6861.
- ^Pikus, G. E.;Titkov, A. N. (1991). "Applications of the Hanle Effect in Solid State Physics".The Hanle Effect and Level-Crossing Spectroscopy.Boston, MA: Springer US. pp. 283–339.doi:10.1007/978-1-4615-3826-4_6.ISBN978-1-4613-6707-9.
- ^Karlov, N.V.; Margerie, J.; Merle-D'Aubigné, Y. (1963)."Pompage optique des centres F dans KBr"(PDF).Journal de Physique(in French).24(10): 717–723.doi:10.1051/jphys:019630024010071700.ISSN0368-3842.S2CID95183756.
- ^Parsons, R. R. (1969-11-17). "Band-To-Band Optical Pumping in Solids and Polarized Photoluminescence".Physical Review Letters.23(20): 1152–1154.Bibcode:1969PhRvL..23.1152P.doi:10.1103/physrevlett.23.1152.ISSN0031-9007.
- ^van ’t Erve, O. M. J.; Friedman, A. L.; Li, C. H.; Robinson, J. T.; Connell, J.; Lauhon, L. J.; Jonker, B. T. (2015-06-19)."Spin transport and Hanle effect in silicon nanowires using graphene tunnel barriers".Nature Communications.6(1): 7541.Bibcode:2015NatCo...6.7541V.doi:10.1038/ncomms8541.ISSN2041-1723.PMID26089110.
- ^Bylicki, F.; Weber, H.G. (1982). "Zero-field Stark level crossing and Stark—Zeeman recrossing experiments in the 593 nm band of NO2".Chemical Physics.70(3): 299–305.Bibcode:1982CP.....70..299B.doi:10.1016/0301-0104(82)88099-3.ISSN0301-0104.