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

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This frequency offset is compensated for in the experimental setup by a method allowing us to tune the frequency output of the MOT master laser over the range needed to operate most of the near-resonance laser tasks. How this is done is shown in Fig. 3.10 which displays the distribution of the MOT master beam in the experiment setup. Most of the MOT master laser output power passes through the 103 MHz AOM unshifted. This portion of the beam H.V. signal from lock-box MOT master laser λ/2 λ/2 Optical Isolator anamorphic prisms pair AOM @ 103 MHz To Saturation Absorption Spectroscopy To Slave Setup Lasers +1 λ/4 λ/2 +1 To Fabry-Perot Cavity PBSC AOM @ 80 MHz Figure 3.10: Distribution of the MOT master laser output. A portion of the beam is sent to the saturation absorption spectroscopy setup to lock the laser. Of the remaining portion, a small amount is sent to a Fabry-Perot cavity to monitor the spectrum. The rest is used to injection lock the slave lasers. double passes an AOM driven at a frequency of 80 ± 20 MHz. This shifts the beam to somewhere between 80-160 MHz to the red of the F = 2 → F ′ = 3 transition. We then use 80 MHz AOMs as fast beam shutters elsewhere in the experiment so that the beams derived from the MOT master laser have frequency detunings 0-80 MHz to the red of the F = 2 → F ′ = 3 transition. This range covers the spectrum needed for a large portion of the near-resonance 104
eams. For example the MOT and optical molasses beams are tuned 15 MHz and 50 MHz to the red of the F = 2 → F ′ = 3 transition, respectively. 3.2.1.2 Slave Lasers The MOT master laser does not produce enough optical power to operate the upper and lower MOT. The frequency stabilization process described in the previous section reduces the output power of the laser diode used in the MOT master laser from its free running level (∼ 100 mW) to roughly ∼ 30 mW. One method of increasing the available power at a particular frequency is to use “slave lasers” frequency locked to a master oscillator. Our experimental apparatus utilizes three slave lasers, each frequency locked to the MOT master laser output. Once locked, the result is three diode lasers with the same spectral properties as the MOT master laser outputting an optical power near their free-running level. Similar to the MOT master laser, the slave lasers are designed around a very inexpensive laser diode. The diode used in each slave laser (Digi-Key: GH0781JA2C) outputs a single-mode near the nominal operating wavelength of 784 nm. Even though the nominal output wavelength is 784 nm, it can be tuned with temperature to the needed value of 780 nm. The maximum free- running optical power of these laser diodes is 120 mW operating at an injection current of 167 mA. Like the MOT master laser diode, each slave laser diode is placed in a collimation tube (Thorlabs: LT230P-B) which is inserted into a bronze holder. 105
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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
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 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: Voltage a b c d e f Frequency Figur
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
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 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
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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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