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

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of 22 ◦ C. The expected vapor pressure is therefore ≈ 3 × 10 −7 torr. This pressure is sufficiently high to rapidly load a MOT in the upper chamber. This MOT serves as a reservoir of atoms which are pushed through the differential pumping tube and recaptured in the lower MOT. The differential pumping tube maintains a pressure differential between the upper and lower chamber allowing long magnetic trap lifetimes in the lower chamber. The differential pumping tube is formed from a 6-3/4 ′′ long 304 stainless steal tube with an outer diameter of approximately 1/2 ′′ . The inner diameter increases in five steps from 1/8 ′′ at the top to 3/8 ′′ at the bottom. This internal taper was made to allow room for the push beam to diverge while still maintaining a sufficiently low conductance, which is calculated to be C ≈ 52 mL/s for this tube [87]. The pumping speed in the lower chamber is 75 L/s resulting in a pressure differential of approximately 1500 between the upper and lower chambers [87]. The expected pressure in the lower chamber is therefore approximately 2 × 10 −10 torr. The top of the differential pumping tube is cut at 20 ◦ to allow diagonal MOT beams to pass unclipped. A MOT is formed in the upper chamber from three pairs of counter-propagating near-resonant beams and two current carrying wire coils, as discussed in Sec. 2.5.2.4. 3.1.2 Middle Chamber The middle-chamber is located directly below the upper-chamber and serves as a hub to attach the vacuum equipment needed to pull, maintain, 90
and monitor the necessary vacuum level in the lower-chamber. This section is necessary because both the upper and lower chambers primarily consist of glass cells, greatly restricting the number of possible connections to other vacuum components. This portion of the vacuum chamber dates back to pre- rubidium days when it was used in experiments performed with cesium. A detailed description of this vacuum chamber section can be found in several dissertations discussing those experiments [88–90] so only a brief overview will be given here. The middle chamber is a modified six-way cross with 4-1/2 ′′ CF flanges. The upper and lower flanges are connected to the upper and lower chamber respectively. The modification of this chamber involved the addition of four half-nipples, each 1-1/2 ′′ long with 2-3/4 ′′ non-rotatable CF flanges attached to one end. These are positioned in between the original 4-1/2 ′′ ports in a plane horizontal to the ground. While this arrangement allows for eight connections to be made to this chamber (not including the connection to the upper- and lower- chambers), only four are currently in use. Attached to one 4-1/2 ′′ flange is an ion pump (Varian 919-0103) with a pumping speed rated at 75 L/s. The pump is supplied with power by a VacIon pump control unit (model 921-0062) operating at 6 kV. A titanium sublimation pump is attached to a second 4-1/2 ′′ flange. This unit has a pumping speed of 300 L/s under normal operating conditions. A hot-cathode, nude Bayard- Alpert style ion gauge is attached to one of the 2-3/4 ′′ flanges. This ion gauge operates in the 10 −3 to mid-10 −10 torr range limiting its usefulness once 91
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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
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 and 102: Chapter 3 Experimental Apparatus Th
Page 103 and 104: Figure 3.1: The vacuum chamber duri
Page 105: Nor-Cal Products Inc. (AMV-1502-CF)
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
Page 153 and 154: h x z magnetically trapped atoms y
Page 155 and 156: 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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