External cavity diode laser around 657 nm

Operating a laser diode in an external cavity, which provides frequency-selective feedback, is a very effective method to tune the laser frequency to a range far from its free running frequency. For the Ca atomic Ramsey spectroscopy experiment, we have constructed a 657-nm laser system based on the Littman-Metcalf configuration with a 660-nm commercial laser diode. Continuously 10-GHz tuning range was achieved with about 100-kHz spectral linewidth, measured with beat-note spectrum of two identical laser systems.     

玻色-爱因斯坦凝聚态的结构理论研究系列之一:玻色-爱因斯坦凝聚态的复合表示理论

针对近零温度下玻色-爱因斯坦凝聚态的特点,建立了复合原子表示模型.提出了复合原子的概念,研究发现复合原子具有一定的零点半径与结合能,得出了相应的表达式.认为该物态作为一个宏观量子态的说法具有相对性,应该据研究角度而定.同时,给出了二个分离的玻色-爱因斯坦凝聚态之间产生1/R型作用势的几种情况,为同类实验提供了理论依据.     

630nm-640nm波段半导体激光频率标准的研究进展

激光频率标准是将激光频率锁定于原子或分子的超精细能级间的稳定跃迁频率,从而获得高精度的激光频率输出[1-3].     

EXPERIMENTAL STUDY ON LASER COOLING OF CESIUM ATOMS BY OPTICAL MOLASSES

We have studied the relationship between the temperature of Cs cold atoms and the parameters of the cooling laser. The atoms are first cooled and captured by a magnetooptical trap and then further coaled by optical molasses. The temperature of atoms la measured by a time-of-flight method. For relatively large laser intensity and small detuning, the temperature depends linearly on the intensity-to-detuning ratio, and nonlinear relationship has alao been found in other case.     

一套实用的铯原子喷泉光学系统的设计及建立

介绍了实现铯原子喷泉的过程及条件,并详细讨论了光路中各种光学元件对铯原子喷泉光学系统性能的影响。在对各种光学元件性能综合考虑的基础上,设计并建立了一套用于进行激光冷却和上抛的铯原子喷泉的光学系统,使光强控制、失谐调整、光束开关、光束质量等多种参量的控制达到了技术要求。在此基础上,实现了铯原子磁光阱,为实现铯原子喷泉奠定了基础。     

Microwave Atomic Clock in the Optical Lattice with Specific Frequency

A scheme for a microwave atomic clock is proposed for Cs or Rb atoms trapped in a blue detuned optical lattice. The ac Stark shift of the clock transition due to a trapping laser is calculated. We analyze it at some specific laser wavelength. Compared with the case of the fountain clock, the cavity related shifts, the collision shift and the Doppler effect are eliminated or suppressed dramatically in an atomic lattice clock. By analyzing various sources of clock uncertainty, a microwave atomic lattice clock with a high accuracy and small volume is feasible.     

一种测量磁光阱中冷原子密度和温度的新方法

报道了对磁光阱中冷铯原子吸收谱的实验观察,由于冷原子的多普勒增宽远小于激光发态超精细分裂,实验观察到三个孤立的吸收峰（Cs,6S1/2,F=4→6P3／2,F＝3,4,5,）其吸收系数比为3：7：12,这与相应跃迁振子强度一致。利用吸收信号测量了冷原子云的密度.结果与荧光探测法在10％的精度内符合;用吸收信号测量了冷原子的温度,测量结果与用荧光飞行时间法和释放捕捉法的结果吻合。     

铯饱和吸收光谱随抽运光强度的变化

研究了铯饱和吸收光谱随抽运光强度变化的情况，特别是６^２Ｓ_１／２Ｆ＝４→６^２Ｐ_３／２Ｆ′＝５的谱线的变化行为．在线偏振光抽运、线偏振光检测的情况下，计入所有相关的Ｚｅｅｍａｎ子能级之间的跃迁，考虑光抽运与饱和效应的共同作用，运用Ｒｕｎｇｅ-Ｋｕｔａ法则求解粒子数方程，计算得出的饱和吸收谱与实验结果符合得较好．还给出了较直观的物理解释 关键词：     

Evaluation of Light Frequency Shift in a Caesium Beam Frequency Standard with Sharp Angle Incident Detecting Laser

Light frequency shift measured in a small optically pumped caesium beam frequency standard is reported and analysed. Two light sources, the diffused laser light scattered from the caesium beam tube parts and the fluorescence light from the beam atoms excited by the laser light, for the light frequency shift are discussed.     

Reduce of the Linewidth of a Diode Laser by Locking to a High-Finesse Fabry-Perot Cavity

We report frequency locking of a commercial 657nm diode laser to a high finesse Fabry-Perot cavity by the_ Pound-Drever-Hall method. The laser linewidth relative to the cavity is estimated to be about 6 kHz.