Experiments to Control Atom Number and Phase-Space Density in ...

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Chapter 3. Single-Photon Cooling 37 3.1 Limitations of Laser Cooling . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.2 A One-Way Wall for Atoms . . . . . . . . . . . . . . . . . . . . . . . . . 38 3.3 Single-Photon Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.4 Maxwell’s Demon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Chapter 4. Rubidium Apparatus 45 4.1 Vacuum System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 4.1.1 Upper Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 4.1.2 Lower Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 4.2 Magnetic Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 4.2.1 Upper MOT Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 4.2.2 Magnetic Trap Coils . . . . . . . . . . . . . . . . . . . . . . . . . . 49 4.2.3 Auxiliary Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.3 Laser System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 4.3.1 Near-Resonant Lasers . . . . . . . . . . . . . . . . . . . . . . . . . 51 4.3.1.1 MOT Master Laser . . . . . . . . . . . . . . . . . . . . . . 52 4.3.1.2 Repump Laser . . . . . . . . . . . . . . . . . . . . . . . . 56 4.3.1.3 Slave Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . 58 4.3.1.4 Upper MOT Horizontal Slave Laser . . . . . . . . . . . . . 60 4.3.1.5 Upper MOT Diagonal Slave Laser . . . . . . . . . . . . . . 61 4.3.1.6 Lower MOT Slave Laser . . . . . . . . . . . . . . . . . . . 62 4.3.2 Far-Detuned Laser . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 4.3.3 Imaging Setups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 4.4 Computer Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Chapter 5. Single-Photon Cooling of Rubidium 67 5.1 Implementation of Single-Photon Cooling in Rubidium . . . . . . . . . . 67 5.2 Branching Ratios and Population Distribution . . . . . . . . . . . . . . . 72 5.3 Effect of the Demon Beam Detuning . . . . . . . . . . . . . . . . . . . . . 72 5.4 Effect of the Demon Beam Position on Atom Number and Temperature . 74 5.5 Transfer Efficiency and Phase-Space Compression . . . . . . . . . . . . . 76 5.6 Monte-Carlo Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 5.7 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Chapter 6. Fock States and Laser Culling 85 6.1 Atomic Fock States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 6.2 Laser Culling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 6.3 Laser Culling of 6 Li Atoms and Qubit Preparation . . . . . . . . . . . . . 87 x
Chapter 7. Lithium Apparatus 92 7.1 Vacuum Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 7.1.1 Oven Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 7.1.2 Differential Pumping Tube . . . . . . . . . . . . . . . . . . . . . . 96 7.1.3 Science Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 7.1.4 Bake-Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 7.2 Magnetic Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 7.2.1 Zeeman Slower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 7.2.2 MOT Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 7.2.3 Feshbach Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 7.2.4 Water-Cooling of MOT and Feshbach Coils . . . . . . . . . . . . . 115 7.3 Optical Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 7.3.1 Near-Resonant Laser System . . . . . . . . . . . . . . . . . . . . . 117 7.3.1.1 Spectroscopy Setup . . . . . . . . . . . . . . . . . . . . . . 117 7.3.1.2 Spectroscopy Cell . . . . . . . . . . . . . . . . . . . . . . . 120 7.3.1.3 Frequency-Offset Lock Setups . . . . . . . . . . . . . . . . 121 7.3.1.4 Tapered Amplifier Setup . . . . . . . . . . . . . . . . . . . 125 7.3.1.5 Imaging Laser Setup . . . . . . . . . . . . . . . . . . . . . 128 7.3.2 CO2 Laser System . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 7.3.3 Optical Setup around the Spherical Octagon . . . . . . . . . . . . 131 7.3.4 Laser Culling Dipole Trap Setup . . . . . . . . . . . . . . . . . . . 133 7.4 Computer Control and Data Acquisition . . . . . . . . . . . . . . . . . . 137 7.5 Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 7.5.1 Absorption Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . 139 7.5.1.1 Absorption Scattering Cross Section at Zero Magnetic Field139 7.5.1.2 Absorption Scattering Cross Section at Large Magnetic Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 7.5.2 Fluorescence Imaging and Calibration . . . . . . . . . . . . . . . . 147 Chapter 8. Towards Fock States of Lithium Atoms 149 8.1 MOT Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 8.2 Compressed MOT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 8.3 Alignment of the CO2 Laser Dipole Trap . . . . . . . . . . . . . . . . . . 155 8.4 Loading of the Optical Dipole Trap . . . . . . . . . . . . . . . . . . . . . 161 8.5 Lifetime of the Optical Dipole Trap . . . . . . . . . . . . . . . . . . . . . 163 8.6 Evaporative Cooling and Trapping Frequencies Measurement . . . . . . . 166 8.7 Future Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 xi
Page 1 and 2: Copyright by Kirsten Viering 2012
Page 3 and 4: Experiments to Control Atom Number
Page 5 and 6: Acknowledgments First of all, I wou
Page 7 and 8: Experiments to Control Atom Number
Page 9: Table of Contents Acknowledgments v
Page 13 and 14: List of Tables 2.1 Physical propert
Page 15 and 16: 4.1 Vacuum chamber . . . . . . . .
Page 17 and 18: 7.39 Future vertical axis optics .
Page 19 and 20: The development of techniques to la
Page 21 and 22: Ptorr 10 5 10 6 10 7 10 8 10 9 260
Page 23 and 24: Property Symbol Value Reference Ato
Page 25 and 26: 2.3.2 Hyperfine Structure So far th
Page 27 and 28: The Wigner-Eckhart theorem can be u
Page 29 and 30: The total magnetic moment of an ato
Page 31 and 32: interaction. The shift in the energ
Page 33 and 34: (a) (b) scattering length a 0 Energ
Page 35 and 36: a laser field with frequency ω. Th
Page 37 and 38: Here ω0 is the resonance frequency
Page 39 and 40: Optical molasses do not provide a s
Page 41 and 42: J=1 J=0 -1 Δ σ + σ - σ - 0 +1 -
Page 43 and 44: phase-space density is defined as
Page 45 and 46: which maintains a constant η = U/k
Page 47 and 48: 2.12.1 Saturated Absorption Spectro
Page 49 and 50: Figure 2.22: Saturation absorption
Page 51 and 52: Signal 0 Signal (a) (b) Signal Freq
Page 53 and 54: (a) (b) (c) (d) Figure 2.24: Absorp
Page 55 and 56: y more complex energy level structu
Page 57 and 58: ight side of the box. An irreversib
Page 59 and 60: time (a) (b) (c) Figure 3.3: Single
Page 61 and 62:
them to move from B to A, but close
Page 63 and 64:
Figure 4.1: Vacuum chamber. Photogr
Page 65 and 66:
( ( Figure 4.3: Helicoflex seal. (a
Page 67 and 68:
88 mm 4.2.3 Auxiliary Coils 62 mm Q
Page 69 and 70:
5 2 P 3/2 5 2 S 1/2 384. 230 484 46
Page 71 and 72:
distribution of the MOT master lase
Page 73 and 74:
shifts. First a frequency shift of
Page 75 and 76:
transition. However, the laser freq
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4.3.1.4 Upper MOT Horizontal Slave
Page 79 and 80:
provides the beam for the upper MOT
Page 81 and 82:
demon beam λ λ horizontal MOT bea
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scholar, Florian Schreck. It is wri
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Atoms are then optically pumped to
Page 87 and 88:
ferred into the |F = 1,mF = 0〉 or
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5.2 Branching Ratios and Population
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effect of the reflected beam at zer
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y the repulsive trough beams, gaini
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Figure 5.9: Atom number as a functi
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Figure 5.10: Radius of the magnetic
Page 99 and 100:
on the collision rate of atoms insi
Page 101 and 102:
ferred via the single-photon coolin
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By comparison an atomic Fock state
Page 105 and 106:
of atoms in the two hyperfine groun
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difference in the lifetimes is dete
Page 109 and 110:
Chapter 7 Lithium Apparatus Creatin
Page 111 and 112:
angle valve rotary feedthrough ion
Page 113 and 114:
an ion gauge controller (Granville
Page 115 and 116:
viewports (MDC, 450002) are attache
Page 117 and 118:
not trapped by the MOT impinge on t
Page 119 and 120:
Should contamination of the vacuum
Page 121 and 122:
Figure 7.12: The assembled Zeeman s
Page 123 and 124:
7.2.2 MOT Coils A second set of coi
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BGauss 250 200 150 100 50 30 20 10
Page 127 and 128:
are required to create the high mag
Page 129 and 130:
The coils are then checked for shor
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+ B A Figure 7.23: Feshbach coil H-
Page 133 and 134:
ensure that no particulates build u
Page 135 and 136:
118 Figure 7.26: Optical layout of
Page 137 and 138:
The error signal shows three lines,
Page 139 and 140:
into the CO2 laser. The optical lay
Page 141 and 142:
Thorlabs PDA10A Coupler ZDC-10-1 to
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Imaging ber Imaging ber from Imagin
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Table 7.4 summarizes the beam power
Page 147 and 148:
CO2 laser 40 MHz AOM f=2 in f=2 in
Page 149 and 150:
132 Figure 7.38: Optical layout aro
Page 151 and 152:
Feshbach coil objective lenses atom
Page 153 and 154:
MOT beams are no longer traveling a
Page 155 and 156:
The second card (NI6733) offers eig
Page 157 and 158:
Averaging over the magnetic subleve
Page 159 and 160:
2 2 P 3/2 D 2=670.977nm 2 2 S 1/2 m
Page 161 and 162:
The right hand side of equation 7.1
Page 163 and 164:
= E0 1 −n2 √2 exp σ0 ± iE0
Page 165 and 166:
esidual potentials besides gravitat
Page 167 and 168:
Figure 8.1: MOT loading. Typical lo
Page 169 and 170:
A linear ramp typically changes the
Page 171 and 172:
A typical MOT is density-limited at
Page 173 and 174:
ubidium [113-115] and cesium[116].
Page 175 and 176:
that most of the noise is due to th
Page 177 and 178:
(a) (c) y . x z X=0.0mm Z=2.5mm 1)
Page 179 and 180:
Figure 8.11: Different shapes of MO
Page 181 and 182:
ZnSe lens f=5 in knife edge ZnSe wi
Page 183 and 184:
shown in figure 8.13. By matching t
Page 185 and 186:
Figure 8.15: Atom number and temper
Page 187 and 188:
275 Hz. Using these values the beam
Page 189 and 190:
system. Maybe the easiest way to ac
Page 191 and 192:
Appendix A Magic Wavelength of Hydr
Page 193 and 194:
transitions for the excited state p
Page 195 and 196:
Bibliography [1] J.J. Thomson. Cath
Page 197 and 198:
[22] C.J. Foot. Atomic Physics. Oxf
Page 199 and 200:
[46] E.D. Black. An introduction to
Page 201 and 202:
[67] J.L. Hanssen. Controlling Atom
Page 203 and 204:
[88] D.S. Naik, C.G. Peterson, A.G.
Page 205 and 206:
[110] J.W. Goodman. Introduction to
Page 207:
[132] C. Degenhardt, H. Stoehr, U.
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