Single-Photon Atomic Cooling - Raizen Lab - The University of ...

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along a horizontal plane through the center of the coils. In this figure the heavily cross-hatched regions indicate wire while the lightly cross-hatched ar- 88 mm 62 mm Quadrupole coil 69 mm 34 mm 158 mm 1.5 mm gap lower glass cell 33 mm 75 mm Quadrupole coil wire layer: C B A nylon spacers Figure 3.24: Schematic of the magnetic trap showing its geometry along a horizontal plane through the center of the coils. eas indicate nylon spacers. Wire sections (A) and (B) each consist of a total of 53 turns while section (C) consists of a total of 70 turns. More detail on the construction of these coils can be found in [83, 84]. As discussed in Sec. 2.4, the field near the center of this arrangement is well approximated with a linear gradient whose value varies with direction. The calculated value of the gradient along the axis of symmetry is 9.7 G/(cm A) and 4.8 G/(cm A) along the radial direction. These values were calculated using Eq. 2.39 and the geometry in Fig. 3.24 and agree well with measured values [84]. The two coils are in series with three power supplies (Lambda GEN80- 126
19) connected in parallel. This arrangement allows us to pass 57 A of current through the coils, although in practice we never exceeded 30 A. The current was regulated with 7 power op-amps (OPA549) placed in parallel and controlled by a homebuilt PID circuit. The details of this current regulator are found in [84]. Each coil has a resistance of 0.29 Ω. With a maximum current of 30A running through each, 261 W of power is dissipated in the form of heat. To re- move this heat water continually flowed across the coils and into a commercial water chiller (Neslab MerlinM100) with a total cooling capacity of 3500W. 3.4 Imaging Systems In Sec. 2.8 I discussed the physics of absorption and fluorescence imaging and how we use the raw data collected to calculate values of interest, such as total atom number. This section deals with the origin of the beams used in the imaging process, their beam paths, and the optics and CCD cameras used to record images. 3.4.1 Vertical Imaging The vertical probe beam is derived from the upper MOT horizontal slave laser as discussed in Sec. 3.2.1.3 and shown in Fig. 3.13. This beam has about 3.5 mW of total power and is tuned to the |F = 2〉 → |F ′ = 3〉 transition frequency. As shown in Fig. 3.25, this beam passes through a λ/2 waveplate allowing it to be combined with the push beam using a PBSC. Before entering 127
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Copyright by Gabriel Noam Price 200
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Single-Photon Atomic Cooling by Gab
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Acknowledgments First, I would like
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Rubidium group when I first joined.
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Single-Photon Atomic Cooling Public
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2.5.2.4 Magneto-Optical Trap . . .
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List of Tables 2.1 87 Rb Physical P
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3.1 Vacuum Chamber . . . . . . . .
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Chapter 1 Introduction This chapter
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the momentum kicks due to absorptio
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samples by allowing for very long i
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Figure 1.2: The energy level struct
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quency regime [19]. This then led t
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Figure 1.4: Depiction of a simple,
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demonstrates the cooling power of a
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a) b) c) external potential one-way
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worked on by Brillouin [27-29], ide
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the atomic ensemble. Not surprising
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are untrappable. The SI unit for en
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the atomic transition and is called
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2.1 Rubidium Rubidium (Rb) is an al
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constant which is given by α = e2
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only one value of J is possible fro
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the latter of which only applies to
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Figure 2.1: 87 Rb D2 Transition Hyp
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Pluging Eq. 2.18 into this Hamilton
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Following the same logic leads to a
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gF = −1/2 using the approximate e
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mize their energy in high magnetic
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If we now consider the field from t
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where P is in torr. The lifetime of
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component of the dipole oscillation
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maxima. Our experiment makes extens
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atoms its wavefunction Ψ(t) is typ
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In this equation we let H = H0 + Hc
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The significance of Isat is that at
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Δ ω =ω−Δ ω =ω−Δ Δ
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where I/Isat ≪ 1 has been assumed
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λ λ Figure 2.9: The Sisyphus cool
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process repeats. If however, it dec
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σ σ σ Figure 2.10: Geomet
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to vary linearly with position alon
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0, ±1 and ∆mF = 0, ±1, allow ex
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this figure only the relevant hyper
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D2 transition in 87 Rb has a natura
Page 91 and 92: 2.7.2 Saturation Absorption Spectro
Page 93 and 94: ground state depletion due to the p
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Page 97 and 98: where n is the number density of at
Page 99 and 100: where σ 2 c = σ 2 2 kBTt n + m .
Page 101 and 102: Chapter 3 Experimental Apparatus Th
Page 103 and 104: Figure 3.1: The vacuum chamber duri
Page 105 and 106: Nor-Cal Products Inc. (AMV-1502-CF)
Page 107 and 108: and monitor the necessary vacuum le
Page 109 and 110: 3.1.3 Lower Chamber The lower chamb
Page 111 and 112: a) top ridge 1 cm b) metal jacket h
Page 113 and 114: to the appropriate frequency throug
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Page 117 and 118: λ Figure 3
Page 119 and 120: Voltage a b c d e f Frequency Figur
Page 121 and 122: eams. For example the MOT and optic
Page 123 and 124: λ Figure 3.12: The slave lasers
Page 125 and 126: λ λ λ
Page 127 and 128: λ λ λ λ
Page 129 and 130: needed when forming a MOT or optica
Page 131 and 132: master laser is dithered at 20 kHz.
Page 133 and 134: λ λ
Page 135 and 136: Output Power > 10 W Wavelength 532
Page 137 and 138: labeled 1, 2 and 3 in the Fig. 3.21
Page 139 and 140: λ λ λ λ
Page 141: process. The two coils are arranged
Page 145 and 146: 3.4.2 Horizontal Imaging The horizo
Page 147 and 148: Chapter 4 Single-Photon Atomic Cool
Page 149 and 150: 1 s, after which time ∼ 10 8 87 R
Page 151 and 152: (a) x z magnetically trapped atoms
Page 153 and 154: h x z magnetically trapped atoms y
Page 155 and 156: z y x magnetically trapped atoms cr
Page 157 and 158: Figure 4.5: The effective potential
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Page 163 and 164: μ μ μ
Page 165 and 166: the potential landscape due to the
Page 167 and 168: Figure 4.12: The number of atoms lo
Page 169 and 170: Figure 4.13: Incremental atom captu
Page 171 and 172: netic trap and transfer into the op
Page 173 and 174: temperature TB of atoms loaded into
Page 175 and 176: used to construct it into the remai
Page 177 and 178: μ μ μ Figure 4.18: Side view of
Page 179 and 180: Figure 4.20: Geometry of the optica
Page 181 and 182: could potentially have undergone th
Page 183 and 184: detunings. The result of scattering
Page 185 and 186: are switched off causing non-optica
Page 187 and 188: Figure 4.25: Number (■) and tempe
Page 189 and 190: traps. If we model the ensembles in
Page 191 and 192: Figure 4.26: Radius of the atomic c
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atoms were removed from the magneti
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trappable |F = 1,mF = −1〉 state
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the short lived 2p state. Atoms whi
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Bibliography [1] R. Frisch, “Expe
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[15] C. C. Bradley, C. A. Sackett,
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[31] E.T. Jaynes, “Information th
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[49] J. Ye, S. Swartz, P. Jungner,
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[66] J.P. Gordon and A. Ashkin, “
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[85] C.-S. Chuu, Direct Study of Qu
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adicals,” Phys. Rev. Lett. 94, 02
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