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

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sheets. Figure 4.10(c) shows the calculated potential along the ˆx direction with y = 0 and z = −50µm. Similarly, the two peaks reflect the potential due to the end caps. The slight curvature of the potential (away from the peaks) is due to the finite Rayleigh length of the lower horizontal sheet. This sheet is focused asymmetrically and therefore has a Rayleigh length associated with each transverse dimension. The Rayleigh length associated with the tight vertical focusing is ZR = 590µm. Finally, Fig. 4.10(d) shows the potential along the ˆy direction with x = 0 and z = −50µm. Here, the two peaks are due to the vertical sheets. The pronounced curvature of the potential (away from the peaks) is due to the 200µm horizontal beam waist of the lower horizontal sheet. The accumulation of atoms into the optical box, a conservative trap, requires an irreversible step. This need is met by optically pumping the atoms that transit the optical box to the F = 1 manifold with the depopulation beam. The beam is near resonant with the 5S1/2(F = 2) → 5P3/2(F ′ = 1) transition and focused to a 1/e 2 waist of 8µm × 200µm at the center of the box. Magnetically trapped atoms in the F = 2 manifold are excited by the depopulation beam and decay with 84% probability to the F = 1 manifold (mF = 1, 0), where they are no longer on resonance with the depopulation beam. Because the gradient of the Zeeman shift of these states is smaller than that of the initial state, the contribution from the magnetic field to the total potential is reduced, creating a trapped state in the optical box in manner identical to that discussed in the previous section. Figure 4.11 show 148
the potential landscape due to the combined magnetic field, optical dipole trap, and gravity for atoms in the |F = 2,mF = 2〉 and |F = 1,mF = 0〉 states, as well as the desired position of the state transfer. F = 2, m F = 2 F = 1, m F = 0 Figure 4.11: The potential landscape due to the combined magnetic field, optical dipole trap, and gravity for atoms in the |F = 2,mF = 2〉 and |F = 1,mF = 0〉 states. Atoms are transfered from the |F = 2,mF = 2〉 state into the |F = 1,mF = 0〉 state by the depopulation beam at the position indicted by the dashed vertical line. As atoms accumulate in the optical box, the outermost trajectories of the magnetic trap are depleted by the depopulation beam. For maximum load- ing into the optical box, we adiabatically translate the center of the magnetic trap towards the optical box by applying a linear current ramp to an auxiliary magnetic coil located above the atoms. 149
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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
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2.7.2 Saturation Absorption Spectro
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ground state depletion due to the p
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oadened background can be removed f
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where n is the number density of at
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where σ 2 c = σ 2 2 kBTt n + m .
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Chapter 3 Experimental Apparatus Th
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Figure 3.1: The vacuum chamber duri
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Nor-Cal Products Inc. (AMV-1502-CF)
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and monitor the necessary vacuum le
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3.1.3 Lower Chamber The lower chamb
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a) top ridge 1 cm b) metal jacket h
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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
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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
Page 157 and 158: Figure 4.5: The effective potential
Page 159 and 160: depopulation present and it indicat
Page 161 and 162: numbers sufficiently large to quant
Page 163: μ μ μ
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
Page 193 and 194: atoms were removed from the magneti
Page 195 and 196: trappable |F = 1,mF = −1〉 state
Page 197 and 198: the short lived 2p state. Atoms whi
Page 199 and 200: Bibliography [1] R. Frisch, “Expe
Page 201 and 202: [15] C. C. Bradley, C. A. Sackett,
Page 203 and 204: [31] E.T. Jaynes, “Information th
Page 205 and 206: [49] J. Ye, S. Swartz, P. Jungner,
Page 207 and 208: [66] J.P. Gordon and A. Ashkin, “
Page 209 and 210: [85] C.-S. Chuu, Direct Study of Qu
Page 211 and 212: adicals,” Phys. Rev. Lett. 94, 02
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