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

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vacuum chamber used for atomic experiments. The two features, rapid MOT loading and a long magnetic trap confinement time, are typically mutually exclusive because the former is favored by a high background vapor pressure while for the latter very low background pressures are required. The double MOT configuration solves this problem by separating the chamber into two re- gions, one of high pressure and one of low, connected by a differential pumping tube. Atoms are rapidly loaded in the high pressure region and then “pushed” with a resonant beam (the so-called push beam) into the low pressure region. To this end, our chamber consists of an upper region maintained at the rubidium vapor pressure, a lower chamber more than three orders of magnitude lower in pressure, and a middle chamber which houses the pumps required to maintain this pressure differential. The entire chamber is shown in Fig. 3.1. This photograph was taken during a vacuum bakeout so the chamber is away from the experiment, allowing a clear view of its elements. The three vacuum chamber sections are indicated in the photograph. 3.1.1 Upper Chamber The upper chamber serves as a high pressure region for quickly accu- mulating 87 Rb atoms in a MOT which are then pushed into the lower chamber. This function is served with a simple design consisting of three main elements: a glass cell, a source of rubidium and a differential pumping tube connecting the upper and lower chamber, as shown in Fig. 3.2. The glass cell is constructed from a rectangular section of Pyrex glass 86
Figure 3.1: The vacuum chamber during a bakeout, away from the rest of the experimental apparatus. The upper, middle and lower portions of the chamber are marked. and has the outer dimensions of 4 ′′ × 1-1/4 ′′ × 1-1/4 ′′ . The chamber walls are 1/4 ′′ thick. The cell is connected to a 2-3/4 ′′ CF steel flange through a graded glass-to-metal seal (Larson Electronics Glass Inc. SQ-150-F2). These two pieces were assembled by Technical Glass Inc. allowing the glass cell to be connected to standard vacuum components. Lower Middle Upper The 2-3/4 ′′ flange at the base of the glass cell is attached to a composite piece of vacuum hardware. This composite piece consists of a 2-3/4 ′′ rotatable half-nipple welded to a rotatable 4-1/2 ′′ blank flange. This piece serves three main purposes. First, it acts as a size adapter allowing the glass cell to be 87
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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
Page 51 and 52: Pluging Eq. 2.18 into this Hamilton
Page 53 and 54: Following the same logic leads to a
Page 55 and 56: gF = −1/2 using the approximate e
Page 57 and 58: mize their energy in high magnetic
Page 59 and 60: If we now consider the field from t
Page 61 and 62: where P is in torr. The lifetime of
Page 63 and 64: component of the dipole oscillation
Page 65 and 66: maxima. Our experiment makes extens
Page 67 and 68: atoms its wavefunction Ψ(t) is typ
Page 69 and 70: In this equation we let H = H0 + Hc
Page 71 and 72: The significance of Isat is that at
Page 73 and 74: Δ ω =ω−Δ ω =ω−Δ Δ
Page 75 and 76: where I/Isat ≪ 1 has been assumed
Page 77 and 78: λ λ Figure 2.9: The Sisyphus cool
Page 79 and 80: process repeats. If however, it dec
Page 81 and 82: σ σ σ Figure 2.10: Geomet
Page 83 and 84: to vary linearly with position alon
Page 85 and 86: 0, ±1 and ∆mF = 0, ±1, allow ex
Page 87 and 88: this figure only the relevant hyper
Page 89 and 90: 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
Page 95 and 96: oadened background can be removed f
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: Chapter 3 Experimental Apparatus Th
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
Page 115 and 116: plexiglass cover piezo U stack grat
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 and 142: process. The two coils are arranged
Page 143 and 144: 19) connected in parallel. This arr
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
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h x z magnetically trapped atoms y
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z y x magnetically trapped atoms cr
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Figure 4.5: The effective potential
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depopulation present and it indicat
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numbers sufficiently large to quant
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μ μ μ
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the potential landscape due to the
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Figure 4.12: The number of atoms lo
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Figure 4.13: Incremental atom captu
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netic trap and transfer into the op
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temperature TB of atoms loaded into
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used to construct it into the remai
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μ μ μ Figure 4.18: Side view of
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Figure 4.20: Geometry of the optica
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could potentially have undergone th
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detunings. The result of scattering
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are switched off causing non-optica
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Figure 4.25: Number (■) and tempe
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traps. If we model the ensembles in
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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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