单原子光镊的激光强度起伏对原子俘获寿命的影响及改善
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摘要
使用单束强聚焦的基模高斯光束可以构建光镊装载原子。虽然光镊一般选择远离原子共振跃迁线的激光,但是光镊的强度起伏仍然会导致原子逃逸,这样原子在光镊中的俘获寿命问题就变得至关重要。本实验以声光频移器(AOM)为主要元件,并施加外部反馈控制电路抑制937.7 nm波长光镊频域上的强度噪声以及时域上的功率起伏,降低光镊对原子的参量加热,从而有效延长原子在光镊中的俘获寿命。典型的频域噪声抑制带宽17 kHz,噪声强度抑制10 dB,时域内激光强度起伏可以从峰峰值起伏±1.350%抑制到±0.036%,有效地降低了光镊的强度起伏。实验结果表明我们可以将937.7 nm波长光镊中单个铯原子俘获寿命从200 ms延长至1 180 ms.为后续原子内态的制备、激发等操作提供充足的时间,保证原子处于俘获状态,提高了实验成功率,缩短了实验时长。
Using a single highly focused fundamental-mode Gaussian beam could form an optical tweezer and load atoms,although optical tweezers generally choose to far away from the atom resonance transition line of the laser, optical tweezers intensity fluctuations will also lend to the atoms' escape,so the lifetime of the atom in optical tweezers becomes crucial.In this experiment, acoustic optical modulator was used as the main component, and a set of external feedback control circuit was added to suppress the intensity noise in frequency domain and power fluctuation in time domain of 937.7 nm optical tweezers,reducing the heating parameters of atoms in optical tweezers, so as to effectively extend the trapping life of atoms in optical tweezers.The typical bandwidth is 17 kHz,noise suppression is 10 dB, and the time-domain laser intensity fluctuation could be reduced from a peak-to-peak fluctuation of ±1.350% to ±0.036%, effectively reducing the intensity fluctuation of optical tweezers. The experimental results showed that the trapping lifetime of single cesium atom in 937.7 nm optical tweezers could be extended from 200 ms to 1 180 ms.It provides sufficient time for the subsequent preparation and excitation of atomic states, ensures the capture of atoms, improves the success rate of experiments, and saves the time of experiments.
Using a single highly focused fundamental-mode Gaussian beam could form an optical tweezer and load atoms,although optical tweezers generally choose to far away from the atom resonance transition line of the laser, optical tweezers intensity fluctuations will also lend to the atoms' escape,so the lifetime of the atom in optical tweezers becomes crucial.In this experiment, acoustic optical modulator was used as the main component, and a set of external feedback control circuit was added to suppress the intensity noise in frequency domain and power fluctuation in time domain of 937.7 nm optical tweezers,reducing the heating parameters of atoms in optical tweezers, so as to effectively extend the trapping life of atoms in optical tweezers.The typical bandwidth is 17 kHz,noise suppression is 10 dB, and the time-domain laser intensity fluctuation could be reduced from a peak-to-peak fluctuation of ±1.350% to ±0.036%, effectively reducing the intensity fluctuation of optical tweezers. The experimental results showed that the trapping lifetime of single cesium atom in 937.7 nm optical tweezers could be extended from 200 ms to 1 180 ms.It provides sufficient time for the subsequent preparation and excitation of atomic states, ensures the capture of atoms, improves the success rate of experiments, and saves the time of experiments.
引文
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[18] Liu B,Jin G,He J,et al.Suppression of Single-cesium-atom Heating in a Microscopic Optical Dipole Trap for Demonstration of an 852 nm Triggered Single-photon Source[J].Phys Rev A,2016,94:013409.DOI:10.1103/PhysRevA.94.013409.
[19] Jin G,Liu B,He J,et al.High on/off Ratio Nanosecond Laser Pulses for a Triggeredsingle-photon Source[J].Appl Phys Express,2016,9:072702.DOI:10.7567/APEX.9.072702.
[20] He J,Liu B,Diao W T,et al.Efficient Loading of a Single Neutral Atom Into an Optical Microscopic Tweezer [J].Chinese Physics B,2015,24(4):043701.DOI:10.1088/1674-1056/24/4/043701.
[21] He J,Yang B D,Zhang T C,et al.Efficient Extension of the Trapping Lifetime of Single Atoms in an Optical Tweezer by Laser Cooling[J].Physica Scripta,2011,84:025302.DOI:10.1088/0031-8949/84/02/025302.
[22] He J,Liu B,Wang J Y,et al.Deterministic Loa Ding of an Indicidual Atom:Towards Scalable Implementation of Multi-qubit[J].Chinese Physics B,2017,26(11):113702.DOI:10.1088/1674-1056/26/11/113702.
[2] Kuhr S,Alt W,Schrader D,et al.Deterministic Delivery of a Single Atom[J].Science,2001,293:278-280.DOI:10.1126/science.1062725.
[3] Schrader D,Dotsenko I,Khudaverdyan M,et al.Neutral Atom Quantum Register[J].Phys Rev Lett,2004,93:150501.DOI:10.1103/PhysRevLett.93.150501.
[4] Xia T,Lichtman M,Maller K,et al.Randomized Benchmarking of Single Qubit Gates in a 2D Array of Neutral Atom Qubits[J].Phys Rev Lett,2015,114:100503.DOI:10.1103/PhysRevLett.114.100503.
[5] He J,Wang J,Yang B D,et al.Single Atoms Transferring Between a Magneto-optical Trap and a Far-off-resonance Optical Dipole Trap[J].Chinese Phys B,2009,18(8):3404-3408.DOI:10.1088/1674-1056/18/8/046.
[6] Liu B,Jin G,Sun R,et al.Measurement of Magic-wavelength Optical Dipole Trap by using the Laser-induced Fluorescence Spectra of Trapped Single Cesium Atoms [J].Opt Expres,2017,25(14):15861-15867.DOI:10.1364/OE.25.015861.
[7] 白乐乐,温馨,杨煜林,等.基于声光频移器反馈控制的397.5 nm紫外激光功率稳定研究[J].中国激光,2018,45(10):1001008.DOI:10.3788/CJL201845.1001008.
[8] Trlcof F,Phung D H,Lours M,et al.Power Stabilization of a Diode Laser with an Acousto-optic Modulator[J].Rev Sci Instrum,2018,89:113112.DOI:10.1063/1.50468520.
[9] Savard T A,KM O’Hara,Thomas J E.Laser-noise-induced Heating in Far-off Resonance Optical Traps[J].Phys Rev A,1997,56(2):1095-1098.DOI:10.1103/PhysRevA.56.R1095.
[10] Gehm ME,K MO’Hara,Savard TA,et al.Dynamics of Noise-induced Heating in Atom Trap[J].Phys Rev A,1998,58(5):3914-3919.DOI:10.1103/PhysRevA.58.3914.
[11] Jarvis K N,Devlin J A,Wall T R,et al.Blue-Detuned Magneto-Optical Trap [J].Phys Rev Lett,2018,120:083201.DOI:10.1103/PhysRevLett.120.083201.
[12] Paul D Lett,Richard N Watts,Christoph Westbrook,et al.Observation of Atoms Laser Cooled Below the Doppler Limit[J].Phys Rev Lett,1988,61:169.DOI:10.1103/PhysRevLett.61.169.
[13] Garcia S,Romain J,Long R.Improving the Lifetime in Optical Microtraps by using Elliptically Polarized Dipole Light[J].Phys Rev A,2018,97:023406.DOI:10.1103/PhysRevA.97.023406.
[14] Kim D,Rhee H G,Song J B,et al.Laser Output Power Stabilization for Direct Laser Writing System by using an Acousro-optic Modulator[J].Rev Sci Instrum,2007,78:103110.DOI:10.1063/1.2801012.
[15] Jonas Junker,PatrickOppermann,Benno Willke.Shor-noise-limited Laser Power Stabilization for the AEI 10 m Prorotype Interferometer[J].Opt Lett,2017,42(4):755-758.DOI:10.1364/OL.42.000755.
[16] He J,Yang B D,Cheng Y J,et al.Extending the Trapping Lifetime of Single Atom in a Microscopic Far-off-resonance Optical Dipole Trap[J].Front Phys,2011,6(3):262-270.DOI:10.1007/s11467-011-0179-y.
[17] He J,Yang B D,Zhang T C,et al.Improvement of the Signal-to-noise Ratio of Laser-induced-fluorescence Photon-counting Signals of Single-atoms Magneto-optical Trap [J].J Phys D:Appl Phys,2011:44135102.DOI:10.1088/0022-3727/44/13/135102.
[18] Liu B,Jin G,He J,et al.Suppression of Single-cesium-atom Heating in a Microscopic Optical Dipole Trap for Demonstration of an 852 nm Triggered Single-photon Source[J].Phys Rev A,2016,94:013409.DOI:10.1103/PhysRevA.94.013409.
[19] Jin G,Liu B,He J,et al.High on/off Ratio Nanosecond Laser Pulses for a Triggeredsingle-photon Source[J].Appl Phys Express,2016,9:072702.DOI:10.7567/APEX.9.072702.
[20] He J,Liu B,Diao W T,et al.Efficient Loading of a Single Neutral Atom Into an Optical Microscopic Tweezer [J].Chinese Physics B,2015,24(4):043701.DOI:10.1088/1674-1056/24/4/043701.
[21] He J,Yang B D,Zhang T C,et al.Efficient Extension of the Trapping Lifetime of Single Atoms in an Optical Tweezer by Laser Cooling[J].Physica Scripta,2011,84:025302.DOI:10.1088/0031-8949/84/02/025302.
[22] He J,Liu B,Wang J Y,et al.Deterministic Loa Ding of an Indicidual Atom:Towards Scalable Implementation of Multi-qubit[J].Chinese Physics B,2017,26(11):113702.DOI:10.1088/1674-1056/26/11/113702.