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
Author Affiliations
Abstract
A method that uses radio frequency (RF) spectroscopy to evaluate the alignment of an optical lattice is proposed and demonstrated. A one-dimensional (1D) optical lattice is applied along the long axis of a cigar-shaped Bose-Einstein condensate (BEC) in a magnetic trap. The RF spectra of condensates with and without the optical lattice are analyzed, measured, and compared with the condition in which the lattice is misaligned with the BEC. The proposed method greatly optimizes the optical alignments of the lattices.
020.1475 Bose-Einstein condensates 020.7490 Zeeman effect 300.6370 Spectroscopy, microwave Chinese Optics Letters
2012, 10(9): 090201
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
Author Affiliations
Abstract
School of Electronics Engineering and Computer Science, Peking University, Beijing 100871
An optical frequency comb phase-locked on an iodine frequency stabilized diode laser at 634 nm is constructed to transfer the accuracy and stability from the optical domain to the radio frequency domain. An external-cavity diode laser is frequency-stabilized on the Doppler-free absorption signals of the hyperfine transition R(80)8-4 using the third-harmonic detection technique. The instability of the ultra-stable optical oscillator is determined to be 7\times10^{-12} by a cesium atomic clock via the optical frequency comb’s mass frequency dividing technique.
120.0120 Instrumentation, measurement, and metrology 300.0300 Spectroscopy Chinese Optics Letters
2009, 7(1): 0136
Author Affiliations
Abstract
Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871
We present a novel design of a compact, stable, and easy-adjustable semiconductor optical amplifier (SOA) system. This SOA system is capable of providing up to 560-mW laser power at the wavelength of 852 nm. For the continuous-wave (CW) seeding laser, the amplification gain can reach 18 dB. We add amplitude modulation onto the CW laser and measure the modulation amplification between seeding and output laser. The amplification gain remains constant within the frequency range from 10 Hz to 1 MHz. The whole system could work in ultra-stable condition: for CW seeding laser, the fluctuation of output power is less than 0.33% in several hours.
半导体光放大器 新结构 高功率输出 幅度调制 超稳定工作 140.4480 Optical amplifiers 140.2020 Diode lasers 140.3325 Laser coupling Chinese Optics Letters
2009, 7(1): 0146
北京大学信息科学技术学院量子电子学研究所, 北京 100871
利用BIBO(BiB3O6)晶体的倍频效应,由半导体激光器产生的波长为846 nm激光可以获得波长为423 nm的蓝光。真空室内的钙炉在加热到600 ℃时产生钙原子束。将423 nm激光垂直照射到钙原子束上,用光电探测器可以获得钙原子束的荧光谱,谱线的半峰全宽(FWHM)为100 MHz。
激光器 倍频技术 荧光谱
Author Affiliations
Abstract
School of Electronics Engineering and Computer Science, Peking University, Beijing 1008712 Beijing Uni-Quanta Co. Ltd, Beijing 100871
Calcium is one prospective element for the modern optical frequency standard. The 423-nm transition line of calcium atoms has been widely used in laser slowing and laser cooling, the precise spectrum measurement, and the magnetic optical trapping (MOT). However, there is no any available commercial diode laser working at this wavelength. We built a 423-nm laser based on extra bow-tie cavity and by using a Brewster-cut uncoated BIBO (BiB3O6) crystal, which worked at room temperature, with conversion efficiency of 3.75%, and a potential up to 20%.
光学频率标准 BIBO晶体 钙原子 020.0020 Atomic and molecular physics 140.0140 Lasers and laser optics 190.0190 Nonlinear optics Chinese Optics Letters
2008, 6(5): 317
