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Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Interferometric Laser Cooling of Atomic Rubidium15.11.17
Jinuk KimQuantum-Field Laser Laboratory
Department of Physics and AstronomySeoul National University, Korea
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Publication list
• 'Algorithmic cooling' in a momentum state quantum computer , Phys Rev Lett 91 037904 (2003)
• Coherent amplification in laser cooling and trapping , PhysRev A 73 033409 (2006)
• Atom cooling using the dipole force of a single retroreflectedlaser beam, Phys Rev A 80 013836 (2009)
• Opto-mechanical cooling with generalized interferometers , Phys Rev Lett 105 013602 (2010)
• Mirror-mediated cooling: a paradigm for particle cooling via the retarded dipole force, Annual Review of Cold Atoms & Molecules 1, 353-378 (2013)
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Contents
Principle of the cooling skim
Experimental implementation
Limitations and advantages
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Mean impulse
0휋2푘휏−
휋2푘휏
푣
푐 ≃1 + cos 푘푣휏 − 휙
2
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
85Rb
|2⟩
|1⟩
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
85Rb
5푃 /
5푆 / 퐹 = 2
5푆 / 퐹 = 3
1
2
11퐺퐻푧
Ω = 2휋 × 400푘퐻푧
depump beam
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Raman pulse generation
780푛푚
+300푀퐻푧
−2.7퐺퐻푧
ECDL : external-cavity diode laserPBSC : polarizing beam splitter cubeTA : tapered amplifierOSA : optical spectrum analyzerBSh : beam shaper and focusing lens
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Spectral filtering - carrier wave removal
퐸 =푒 푐표푠휃푒 푠푖푛휃 퐸 =
푒 ( )푐표푠휃푒 푠푖푛휃
=퐽 (푚)푐표푠휃
푠푖푛휃 푒 +푐표푠휃0 푒 푖 퐽 푚 푒
EOM
PBS(transmission axisorthogonal to
polarization of the carrier)
carrier wave and sidebands have different polarizationEOM
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Spectral filtering – unwanted sideband removalMach-Zehnder interferometer
EOM
휔 휔
maximized when phase difference of two path : 훿 휔 = 0, 훿 휔 = 휋
refractive index depends on the temperaturedestructive interference
constructive interference
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Raman velocimetry
5푃 /
5푆 / 퐹 = 2
5푆 / 퐹 = 3
1
2
MOT beam
repump beam
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Timing diagram of experiment
cooling velocity distributionmeasurement
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Result
(3.2 ± 0.4)휇퐾
(21 ± 2)휇퐾
(10 ± 1)휇퐾
4.8 ± 0.5 휇퐾
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Advantage
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Advantage
Your Occasion November 24, 2015
Seoul National University Quantum Field Laser Laboratory
Cooling atoms with microwave
It is impossible to cool atoms with microwave analog to magneto optical trap. Because fast spontaneous emission is a crucial part of MOT for initializing atoms and removing entropy of the atoms.
There is a paper about cooling an artificial atom with microwave.Principle of their method is the same as optical cooling of trapped ion.Valenzuela, S.O. et al. Microwave-induced cooling of a superconducting qubit. Science 314, 1589-1592 (2006)
