Optical Pumping
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Optical Pumping By David Ray I also am quite excited I’M SO PUMPED FOR !IS"""
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Transcript of Optical Pumping
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Optical PumpingBy David RayI also am quite excitedIM SO PUMPED FOR THIS!!!1IntroductionWhat am I presenting?Historical BackgroundDiscovered By Alfred Kastler
Led to the development of lasers
Awarded Nobel Prize in 1966
Angular MomentumCaesium:1s22s22p63s23p63d104s24p64d105s25p66s1LSJIF[Xe]6s1Fine structureHyperfine structure6s6p6s1/26p3/26p1/2F=5F=4F=4F=3F=4F=3(I=7/2)Zeeman EffectFmFmF =-F,-F+1,,FF=1mF=1mF=0mF=-1FFmFHyperfine structureZeemanEF = gF B |B| mFEF EF (gF=1/4)Pumping Right circularly polarised light imposes absorption selection rule mF=+1Spontaneous emission selection rule mF=-1,0,1F=1p1/2-1mF01F=1s1/2ZeemanNo available transitoni.e. atoms PumpedTransitionsGround stateSpontaneous Emission Photon approaches electron Photons absorbed Electron emits photon in random direction Excited stateSpontaneous emissionStimulated Emission Electrons in excited state Photon matching E approaches electronE Stimulates emission of photonExcited statePhoton approachesStimulated emissionRabi OscillationsSystem is Pumped Stimulated emissionStimulated emissionStimulated emissionStimulated emissionAbsorption Population is the percentage of electrons in a given stateRabi oscillations are the fluctuations of the population with respect to timeP(ground) sin2(t/2)P(ground) + P(excited) = 1 2MethodologyHow will this be achieved?Equipment
http://spa-mxpweb.spa.umn.edu/s11/Projects/S11_OpticalPumping/apparatus.htmCaesium lamp(temperature controlled)Interference filterQuarter-wave plateHorizontal field & Sweep fieldPhoto-detectorFocusing lensRF coilLinear polariserFocusing lensCaesium ChamberLight rackEarths Magnetic Field PhotorackOscilloscopeSweeping field & Horizontal FieldRF field Photorack provides a channel to oscilloscope based on opacity of Caesium Chamber This is dependant on this equationEF = gF B |B| mF When B is such a value thathf = gF B |B| mFOpacity will drop|B| = (BC+BE||)2 +BE 2 Rabi oscillationsPhotorackOscilloscopeHorizontal FieldRF fieldPulse Generator RF field is periodically turned off Plot a curve to fit resulting oscillations3ResultsWhat was observed?Earths Magnetic FieldPlotted fres vs. B By: hf = gF B (BC+BE||)2 +BE2 mFA occurs when BE|| =-BCGraphs linear when BE ~0BE = 50.3 2.3 T
AB/Tfres/HzRabi Oscillations
Fitted e-at+sin(t)+c corresponds to Rabi frequency = 4736 5 Hz4ConclusionWhat does this all mean?
