Author Affiliations
Abstract
1 Institute of Quantum Electronics, School of Electronics, Peking University, Beijing 100871, China
2 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
To obtain cold atom samples with temperatures lower than 100 pK in the cold atom physics rack experiment of the Chinese Space Station, we propose to use the momentum filtering method for deep cooling of atoms. This paper introduces the experimental results of the momentum filtering method verified by our ground testing system. In the experiment, we designed a specific experimental sequence of standing-wave light pulses to control the temperature, atomic number, and size of the atomic cloud. The results show that the momentum filter can effectively and conveniently reduce the temperature of the atomic cloud and the energy of Bose–Einstein condensation, and can be flexibly combined with other cooling methods to enhance the cooling effect. This work provides a method for the atomic cooling scheme of the ultra-cold atomic system on the ground and on the space station, and shows a way of deep cooling atoms.
momentum filter standing-wave pulse Bose–Einstein condensation optical dipole trap two-stage cooling space station Chinese Optics Letters
2023, 21(8): 080201
Author Affiliations
Abstract
Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
We propose, design, and realize a compact stabilized laser system that can be tuned within 24 GHz automatically. This laser system consists of two distributed feedback (DFB) lasers, one of which is reference and locked to the D2 line of Rb87, the other laser is a slave that is locked to the reference laser via a loop servo. We measured the frequency of the beating signal of the two lasers and generated an error signal, which controlled the frequency of the slave laser to close the loop. We compressed the fluctuation of the beating signal’s frequency to less than 1 MHz. Furthermore, the system can also automatically determine and control whether the slave is red detuned or blue detuned to the reference. The dimensions of our laser system are about 15 cm × 20 cm × 10 cm. This kind of laser system can be applied in many important applications, such as atomic interferometer and cold atomic clock.
140.2020 Diode lasers 140.3425 Laser stabilization Chinese Optics Letters
2018, 16(3): 031403
设计并实现了一种低功耗、小型化、可长期稳定运行的自动稳频激光系统。通过设计并实现高效率、低纹波的电压源，较大幅度地降低了整个系统的功耗和体积；通过设计并实现高性能温度控制电路、电流控制电路和稳频电路，得到了线宽较窄、频率稳定度较高的输出激光。该系统能够自动长期稳频，输出激光线宽约为1 MHz，稳定度指标为秒稳定度1.43×10-10，十秒稳定度3.90×10-11，百秒稳定度1.28×10-11，千秒稳定度2.25×10-11。在稳定度略优于商用外腔半导体激光器的前提下，该激光系统电源体积缩小了约85%，整机功耗降低了约90%，为实现半导体稳频激光系统的低功耗和小型化提供了一种新的方案。
激光器 频率稳定度 饱和吸收谱 低功耗 小型化
1 北京大学信息科学技术学院, 北京 100871
2 中国科学院上海光学精密机械研究所, 上海 201800
研制了一种高均匀性、小型化的法拉第磁光隔离器，用于780 nm波长的光路中，并对设计方案进行了数值模拟和验证。采用了新颖的三段式“π”形磁体的组合设计方案， 提高了剩磁利用率。隔离器整体体积为52 cm3，其中磁体体积为18 cm3，是相当小的。它的通光孔径为5 mm，隔离比为34.6 dB，透过率为90.9%。与之类似的 “II”型磁体体积更小，磁场均匀性稍差，也是可行的设计方案。成品隔离器比商用隔离器磁场均匀度更高，体积更小，隔离比更高，可以有效满足研发中的冷原子平台的 小型化、高精度需求。
激光器件 法拉第磁光隔离器 数值模拟 玻色-爱因斯坦凝聚 冷原子 laser devices Faraday optical isolator numerical simulation Bose-Einstein condensation cold atom
北京大学信息科学技术学院量子电子学研究所, 北京 100871
玻色-爱因斯坦凝聚 (BEC) 是当前原子分子物理的一个国际前沿课题。 自从1995年在激光冷却的基础上实现BEC以后,全世界已有几十个研究小组成功地获得了BEC, 并取得了一批引人注目的成果。研究玻色凝聚体的动量操控是超冷量子气体研究的重要研究方向, 北京大学研究小组于2004年在实验上获得铷原子玻色凝聚以来,在玻色凝聚体的超辐射散射方面作了 一系列研究工作,主要介绍该研究组近五年来利用超辐射散射在铷原子玻色凝聚动量操控方面的研究工作。
玻色-爱因斯坦凝聚 超冷量子气体 超辐射散射 动量操控 Bose-Einstein condensate quantum gas superradiant scattering quantum manipulation
1 北京大学信息科学技术学院电子学系量子电子学研究所, 北京 100871
2 中国科学院上海光学精密机械研究所, 上海 201800
新一代光纤飞秒光梳在精密测量和基础物理研究领域中有着广阔的前景, 一种通过数字电荷泵锁相环和温控电路相结合的方法可以精密控制光纤飞秒光梳。 成功搭建了光纤飞秒光梳系统。光梳的重复频率为129 MHz,初始频率大约为33 MHz。 通过自主研发的温控和数字电荷泵锁相环成功地把光纤飞秒光梳锁定在了由Agilent PSG Analog Singal Generator提供的标准微波信号上,锁定时间至少长达1天。锁定后重复频率的抖动标准差为0.78 mHz, 与基准源同一个数量级且很接近,锁定后初始频率的抖动标准差达8.98 Hz。
激光技术 光纤飞秒光梳 光梳稳频 数字电荷泵锁相环 laser techniques fiber-based femtosecond optical frequency comb stabilization of optical comb frequency digital charge-pump phase-locked loop
Author Affiliations
Abstract
School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
A laser power feedback control system that features fast response, large-scale performance, low noise, and excellent stability is presented. Some essential points used for optimization are described. Primary optical lattice experiments are given as examples to show the performance of this system. With these performance characteristics, the power control system is useful for applications in cold atom physics and precision measurements.
激光功率 反馈控制 大范围 快速响应 光晶格 140.3425 Laser stabilization 020.1475 Bose-Einstein condensates 000.3110 Instruments, apparatus, and components common to the sciences Chinese Optics Letters
2011, 9(9): 091403
Author Affiliations
Abstract
Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
Two extended-cavity diode lasers at 780 nm which are longtime frequency-stabilized to Rb87 saturated absorption signals are reported. A high-performance frequency-locking circuit module using a first-harmonic detection technique is designed and achieved. Two lasers are continuously frequency-stabilized for over 100 h in conventional laboratory condition. The Allan standard deviation of either laser is estimated to be 1.3×10-11 at an integration time of 25 s. The system environment temperature drift is demonstrated to be the main factor affecting long-term stability of the stabilized lasers based on our correlation study between beat frequency and system environment temperature.
半导体激光器 稳频 阿伦方差 连续锁定时间 140.2020 Diode lasers 140.3425 Laser stabilization 250.5960 Semiconductor lasers Chinese Optics Letters
2010, 8(5): 496
北京大学信息科学技术学院量子电子学研究所，北京 100871
介绍了633 nm半导体激光频标系统，高重复频率锁相飞秒激光器系统和绝对频率测量系统的建立以及测量碘分子超精细跃迁绝对频率的系统方案。633 nm半导体激光频标采用三次微分稳频方法，将激光频率锁定在碘分子谱线上，获得0．5 mW的稳频激光输出。飞秒激光稳频系统通过锁相电路将飞秒激光的高重复频率(760 MHz)和初始频率稳定在微波频率标准上，从而得到稳定的飞秒光梳，其稳定度优于6．44×10－13。在此基础上建立了绝对频率的直接测量系统，即利用波长计直接测量光梳的齿数n，并通过拍频法，测出633 nm半导体激光频标与飞秒光梳的差频，从而计算出相应谱线的绝对频率。这样，通过锁相飞秒激光器，建立了微波频率标准到光学频率标准的传递，为进一步的基础研究工作奠定了基础。
激光技术 绝对频率测量 飞秒激光器 锁相电路 外腔半导体激光频标 稳频 lasertechniques absolute frequency measurement femto-second laser phase locked circuits frequency standard of ECL frequency stabilization
