Miniaturized optical system for atomic fountain clock

Using modularized components, we have built a miniaturized optical system for 87Rb atomic fountain clock that is fitted on an 80 cm × 60 cm optical breadboard. Compared with the conventional optical setup on the table, our system is more compact, more robust and miniaturized. Taking advantage of this system, laser beams are transmitted through eight optical fibre patch cords from the optical breadboard to an ultra high vacuum system. This optical setup has operated for five months in our fountain system and required no alignment.     

Fold optics path: an improvement for an atomic fountain

A fold optical path is utilized to capture and launch atoms in the atomic fountain.This improved technique reduces the laser power needed by 60 percent,facilitates suppression of the laser power fluctuations,and leads to a more simple and stable system.     

Loading of cold ~(87)Rb atom with diffuse light in an integrating sphere

<正>Cold ~(87)Rb atom's loading in an integrating sphere with diffuse light is analyzed theoretically and experimentally. The experimental results show that diffuse light cooling has the greatest efficiency to cool the most atoms when the red detuning between the frequencies of cooling light and atom transition is about 3.3r(Γis the natural linewidth,6.065 MHz).Theoretical analysis using rate equation and numerical calculations on the cold atom number and loading time agree with the experimental results.This integrating sphere cooling would be a novel method for cooling atoms and lead to a new and robust cold atom source for atomic clock.     

Saturation of biphoton generation near atomic resonance

We have numerically investigated the biphoton generation rate as a function of several parameters in the spontaneous four-wave mixing in cold atoms.It has been found that the biphoton generation rate can easily reach saturation with the intensity of the coupling laser increasing.The saturation intensity is mainly dependent on the dephasing rate of the ground states,unrelated to the pumping laser.It implies that though the biphoton waveform can be manipulated by the coupling laser,the generation rate of the biphoton cannot increase markedly after the saturation.The saturation effect also suggests that there is an optimal coupling laser for obtaining the largest biphoton generation rate with a sufficiently long coherence time.     

Guiding Neutral Atoms with Two Current-Carrying Wires and a Vertical Bias Field on the Atom Chip

We demonstrate the guiding of neutral atoms with two parallel microfabricated current-carrying wires on the atom chip and a vertical magnetic bias field. The atoms are guided along a magnetic field minimum parallel to the current-carrying wires and confined in the other two directions. We describe in detail how the precooled atoms are efficiently loaded into the two-wire guide. We present a detailed experimental study of the motional properties of the atoms in the guide and the relationship between the location of the guide and the vertical bias field. This two-wire guide with vertical bias field can be used to realize large area atom interferometer.     

Trapping of Neutral^87Rb Atoms on an Atomchip

We report an experiment of trapping of neutral ^87Rb atoms on a self-made atomchip. The H-shaped atomchip is made by magnetron sputtering technology, which is different from the atomchip technology of other teams. We collect 3×10^6 ^87Rb atoms in the mirror magneto-optical trap （MOT） using the external MOT coils, and 1×10^5 ^87 Rb atoms are transferred to U-MOT using U-shaped wire in chip and a pair of bias coils.     

激光稳频技术的新发展(Ⅲ)──脉冲激光器的稳频技术和激光波长测量

脉冲激光器的频率稳定和测量,一向是一个较棘手的问题.但近年来,随着脉冲激光器在激光化学、激光光谱、激光雷达和外差检测系统等方面应用的发展,迫使人们去探索稳定脉冲光频的方法.下面介绍的几种脉冲激光稳频方法. 一、长期稳腔式[1]; 稳腔长当然可以稳定光频,但脉冲的持续时间短,较难判断腔长是否已被稳定,故采用一种长期稳腔的方案.这个方案在TEA CO2激光器中得到较合理实施,系统如图1所示,将TEA激光头和连续CO2器件置于同一谐振腔内,以构成混合式TEA激光器,获得单纵模振荡.通过连续器件的光电流稳频系统,以某一谱线(P或R的某一支…     

微重力环境下冷原子物理及其应用

文章介绍了国际上微重力环境下冷原子物理及其应用的研究工作：空间原子钟、原子干涉仪、超冷原子物理和建议中的广义相对论的探索。文中简要介绍了中国科学院上海光学精密机械研究所在微重力环境下所进行的空间原子钟、玻色-爱因斯坦凝聚和原子芯片等研究工作。     

The application of sample-and-hold circuits in the laser frequency-shifting

Lasers with stable frequencies are essential in manyfields of research[1-4] such as in laser cooling andtrapping atoms[5] and Bose-Einstein condensationexperiments[6,7]. It is required that the line width oflasers is less than 1 MHz and does not have long-termdrift. Yet on some occasions, it is often necessary torapidly shift the frequencies of cooling beams from thedetuning -2Γ - 3Γ to -6Γ - 8Γ (Γ is the natural widthof the atom) to lower the temperature[8,9]. Normally, wehave two mean…     

利用原子束研究光的力学效应

本文介绍了我们利用原子束研究光的力学效应的原理、方法和主要结果．我们测量了激光偏转原 子束的原子空间分布，观察了在光场作用下原子动量的扩散，验证了二能级原子共振荧光中亚泊松光子，统计分布，研究了慢原子在驻波场中的运动行为，提出了沟道原子光谱技术的新方法，并用这种方法观 察了钠原子的超精细结构．