Autler–Townes spectroscopy of high-lying state by phase conjugate six-wave mixing

An Autler-Townes(AT) spectroscopy based on phase conjugate six-wave mixing(SWM) is proposed to detect AT doublet of high-lying state in a Doppler-broadened cascade four-level system.It is found that the SWM spectrum is dependent strongly on the ratios between the magnitudes of the wave vectors.We discuss how the Doppler broadening affects the SWM spectrum from a time-domain viewpoint and find that,due the atomic motion,the atomic polarizations acquire different phases for atoms with different velocities as time evolves.The Doppler free SWM spectrum can be obtained only when the atomic polarization can be rephasing again at certain time after the interactions of all the incident fields.     

Enhanced Loading of ~(40)K from Natural Abundance Potassium Source with a High Performance 2D~+ MOT

~(40)K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low concentration(0.012%) of ~(40)K in natural abundance of potassium, most experiments use 4–10% enriched potassium source, which have greatly suffered from the extremely low annual production and significant price hikes in recent years. Using naturally abundant potassium source, we capture 5.4 × 10~6 cold ~(40)K atoms with the help of a high performance of two-dimensional magneto-optical trap(2D~+MOT), which is almost three orders of magnitude greater than previous results without the 2D~+ MOT. The number of the ~(40)K atoms is sufficient for most ultra-cold ~(40)K experiments, and our approach provides an ideal alternative for the field.     

发展固态量子信息与计算的实验研究

量子计算与量子信息是21世纪基础和应用科学研究的一大挑战.要实现实用意义上的量子信息和量子计算,必须解决量子比特系统的可拓展性问题.基于现代半导体技术的固态量子系统,其应用和最终产业化的可行性较高.然而,固态量子体系受周边环境的影响比较严重,控制其退相干,维持其量子状态的难度更高.实验固态量子计算的研究是个新的领域,尚无实用的技术和方法. 文章介绍了中国科学院物理研究所固态量子信息和计算实验室近几年来新开辟的自旋、冷原子、量子点(包括原子空位)、功能氧化物和关联体系等固态量子信息的新载体和同量子计算与量子信息相关的科学与技术难题的实验研究.     

Rb87冷原子电磁感应透明吸收曲线不对称性的分析

研究了耦合光共振时Rb⁸⁷冷原子D1线Λ形能级体系中电磁感应透明吸收曲线的不对称现象.发现间隔为814 MHz的另一个激发态能级导致了不对称现象.不对称现象的根本原因是受激拉曼散射, 同时发现透明窗口两侧不对称的吸收峰的幅值比与耦合光强成正比.理论拟合与实验数据符合得较好.     

出人意料的电子电偶极矩上限

<正>几十年来,实验物理学家都在尝试利用原子或分子束技术来测量电子的电偶极矩(EDM)。尽管还没有测出电子电偶极矩的具体大小,他们却不断地给出了更精确的电子电偶极矩上限值。这些实验通常在普通实验室的光学平台上进行,却对粒子物理研究有重要价值,而粒子物理实验通常是在巨大的粒子加速器上进行的。不少物理学家认为,EDM实验是用于研究超出粒子物理标准模型的新物理的最快和最廉价的手段。电子在自然定律违反时间反演     

Ultra-High Efficiency Magnetic Transport of SZRb Atoms in a Single Chamber Bose-Einstein Condensation Apparatus

We report the ultra-high efficiency transport of cold ST Ftb atoms using a moving magnetic quadrupole potential generated by three overlapping pairs of fixed coils. The transfer etticiency is better than 97%, which is the highest ever reported to our knowledge. The temperature increase due to heating is less than IO #K when the initial cloud temperature is llO#K. Our setup is similar to the magnetic transferring belt design [Phys. ftev. A 63 （2001）031401（R）], although it is simpler because the push coil is not required. We use it to transport atoms away from a magneto-optical trap to very close to the wall of the glass cell, facilitating future experiments employing three-dimensional optical lattices, high resolution in-situ imaging, and magnetic Feshbach resonances.     

Spin dynamics of the potassium magnetometer in spin-exchange relaxation free regime

The laser-pumped potassium spin-exchange relaxation free(SERF) magnetometer is the most sensitive detector of magnetic field and has many important applications. We present the experimental results of our potassium SERF magnetometer. A pump–probe approach is used to identify the unique spin dynamics of the atomic ensemble in the SERF regime.A single channel sensitivity of 8 f·THz-1/2is achieved with our SERF magnetometer.     

铷蒸气Λ-型系统中的受激Raman谱与光泵效应

从理论和实验上研究了⁸⁵Rb 原子蒸气D1线系统中的受激Raman现象. 在Λ-型能级系统中, 抽运光对弱探测光的影响有两部分: 受激Raman激发和光泵效应. 在一定的抽运光强度和失谐量条件下, 受激Raman谱表现为增益谱或损耗谱; 以光泵效应导致的吸收谱为背景时, 便分别形成了窄线宽透明窗口或线宽差异很大的吸收双线. 理论模拟和实验结果基本符合. 基于这些研究, 从新的角度阐述了在Λ-型系统中的电磁感应透明和Autler-Townes分裂这两个重要现象与受激Raman谱之间的关系. 关键词： 受激Raman谱 光泵效应 电磁感应透明 吸收双线     

铷原子耦合光频率近共振时的电磁感应透明

研究了Λ型能级系统中, ⁸⁵Rb原子在耦合光频率失谐较小时的电磁感应透明(EIT)现象. 实验中, 随着耦合光频率失谐量的增加, 电磁感应透明窗口的绝对强度有所减弱, 但是其相对深度却有所增加, 透明窗口相对深度最大的位置不在耦合光频率共振处, 而是在耦合光频率失谐约180 MHz的位置. 用三能级和四能级系统的理论分别对实验结果进行对比分析, 发现用四能级系统的理论进行拟合的结果与实验符合得比较好. 对此, 我们提出当耦合光频率失谐较小时, EIT信号是两个激发态共同作用的结果, 并用四能级系统的理论分析了两个激发态之间的能级间隔对透明窗口相对深度最大值位置的影响.     

多模1064nm光纤激光器实现一维远失谐光晶格

采用1064 nm多模30 W连续光纤激光器, 搭建了一个周期为25 μm的一维远失谐光学晶格势场. 对铷原子进行磁光阱装载和偏振梯度冷却, 实现了铷冷原子团在光晶格中的装载. 借助于短程飞行时间法, 测量晶格中冷原子温度为20 μK, 为下一步实现量子信息存储实验奠定了基础.