Hyperfine Studies of Hyperfine Studies of Lithium usingLithium using
Saturated Absorption Saturated Absorption SpectroscopySpectroscopy
Tory CarrTory Carr
Advisor: Dr. Alex CroninAdvisor: Dr. Alex Cronin
Hyperfine Structure of Hyperfine Structure of 66Li & Li & 77LiLi
Normal SetupNormal SetupT
rans
mis
sion
Sig
nal
-15 -10 -5 0 5 10 15frequency (GHz)
6Li D1
7Li D1+
6Li D2
7Li D2
Theoretical LimitTheoretical Limit
8
6
4
2
0
Inte
nsity
0.20.10.0-0.1-0.2Frequency (GHz)
6 MHz
ProblemProblem
Doppler Broadening “smears out” Doppler Broadening “smears out” resolutionresolution
Inte
nsity
420-2-4Frequency (GHz)
3 GHz
Normal SetupNormal SetupT
rans
mis
sion
Sig
nal
-15 -10 -5 0 5 10 15frequency (GHz)
6Li D1
7Li D1+
6Li D2
7Li D2
Theory at 375 C
Saturated Absorption SetupSaturated Absorption Setup
New SpectrumNew Spectrum30x10
-3
25
20
15
10
5
0
Tra
nsm
issi
on s
igna
l (m
W)
151050-5-10-15Frequency (GHz)
FS
HFS
HFS
7Li D2
7Li D1+
6Li D2
6Li D1
experimental data theoretical model
Saturated Absorption SignalSaturated Absorption SignalT
rans
mis
sion
Sig
nal
Frequency Scan
800MHz
Data collected at 375 C
Light as seen from the Light as seen from the atomsatoms
Pump beam
probe beamv0
Population DifferencePopulation Difference
Scan in frequencyScan in frequency
+dv
-dv
0
Theoretical ModelTheoretical Model
Isotope/ Transition Isotope/ Transition DifferenceDifference
Variation with Buffer Gas Variation with Buffer Gas PressurePressure
Temperature variationTemperature variation
Temperature variation- diff Temperature variation- diff sigsig
Maximum in difference Maximum in difference signalsignal
Maximum Signal When:
ConclusionConclusion
Limiting Factors in resolutionLimiting Factors in resolution– Other broadening mechanismsOther broadening mechanisms– Residual Doppler broadeningResidual Doppler broadening
Improvements to setupImprovements to setup– Improved alignmentImproved alignment– Reduce laser linewidthReduce laser linewidth
Further experimentsFurther experiments– Effects of polarizationEffects of polarization– Magnetic field effects Magnetic field effects