原子束计算全息技术的原理与实现

提出用计算全息技术来实现原子束全息成像，降低了原子束全息的实现难度.首先论述了原子束的波动性质以及如何形成相干性能良好的准单色原子波包，然后讨论了原子束计算全息片的设计步骤，并给出了制作完成的SiN薄膜计算全息片，最后详细介绍了原子束全息的实现方案.     

原子光学讲座第一讲几何与波动原子光学及其器件

文章首先简单介绍了冷原子操纵与控制的基本原理。然后，重点介绍了几何与波动原子光学及其器件的研究内容、潜在应用和最新进展，其中包括：原子束的反射和原子反射镜；原子束偏转（折射）、聚焦成像和原子透镜；原子衍射和原子光栅；原子干涉和原子干涉仪；原子全息学及其技术等。     

原子束计算全息片的设计与制作研究

在分析原子束计算全息片特点的基础上,提出采用罗曼Ⅲ型傅里叶变换计算全息图设计原子束计算全息片,给出设计步骤,然后提出采用电子束光刻编码矩孔图形,ICP各向异性刻蚀SiN薄膜的全息片制作方案,对全息片的制作工艺流程详细予以介绍,最后给出制作完成的SiN薄膜计算全息片.     

非漫射物双曝光全息图的白光再现

一、引言全息干涉计量的基本过程与全息记录相似,只是在记录中根据需要有时进行一次曝光(实时全息干涉法)、两次曝光(双曝光全息干涉法)和连续曝光(时间平均全息干涉法)等。它们的原理都是基于波前的干涉.这里主要讨论非漫射物的双曝光全息图的白光再现。     

反向旋转双色椭偏场中原子隧穿电离电子的全息干涉

利用数值求解含时薛定谔方程和强场近似理论研究了反向旋转双色椭偏光场中氩原子隧穿电离电子的干涉.固定两脉冲的椭偏率均为0.3,当两椭偏场的相对相位为0.25π时,光电子动量谱中周期内干涉、叉状全息干涉和弧形全息干涉相互重叠.当两椭偏场的相对相位为0时,光电子动量谱中弧形全息干涉消除,并且周期内干涉和叉状全息干涉被彻底分离到动量谱的左右部分,从而得到一个在空间上独立的叉状全息干涉条纹.进一步研究表明,通过改变两椭偏光场的椭偏率还可以增强或抑制该独立叉状全息干涉条纹.这为干涉条纹的控制和分离提供了一个有效的手段,同时也有利于从全息干涉条纹中提取靶材结构信息和电子超快动力学信息.     

电子学全息干涉术用于温度场测量

探讨了用电子学全息干涉术（双称数字全息干涉术）测量温度场分布及其变化的可行性，利用所设计的全息干涉实验光路，对一电烙铁头部周围温度场分布进行了实时全息记录，进而利用一维快速傅里叶变换及数字滤波处理再现出了反映温度场分布的全息干涉条纹图样，实验结果表明，与传统的光学全息干涉术相比，电子学全息干涉术借助于高分辨率CCD记录及高速计算机数字处理技术，从而可实现光学全息图的数字化记录、存储和重现。同时，利用再现物场相位倍增原理还可实现对干涉条纹数目的倍增，或利用物场相位分布的直接计算精确获取任意两点间的相位差，从而提高测量精度。此外，由于能够在不改变光路的前提下以较高的重复频率完成光学全息图的记录，电子学全息干涉术可以用于记录三维物场的变化并接近实时地再现和测量三维物场的变化规律，因此是一种极有发展前途的新型实时全息干涉计量技术。     

在粗糙表面上用液晶空间光调制器进行振动测量

为实现在一段时间内连续实时观测振动物体的全息干涉图形,采用覆盖铝箔的喇叭作为振动物体,利用铝箔原有未经特殊处理表面反射的漫反射光成像,并用光寻址液晶空间光调制器(Liquid crystal-sparial lightmodulator,LC-SLM)作为全息记录载体,来实现振动测量。实验中采用时间平均干涉测量法,得到了不同振动频率下物体的干涉图形。同时在连续改变振动物体的振动频率时,可以清晰地观察到物体振动全息干涉图形的变化过程,即近实时的全息干涉图形。     

基于菲涅耳双棱镜分波前干涉装置的全息光栅制作实验

不同于传统全息光栅制作教学实验中的分振幅干涉光路,提出了利用准平行相干光源照射菲涅耳双棱镜实现分波前干涉制作全息光栅的方法.利用菲涅耳双棱镜分波前光路分别演示了单个双棱镜制作一维全息光栅和2个棱脊正交菲涅耳双棱镜制作二维全息光栅.实验过程中可通过多种方法对干涉条纹间距和光栅常量进行估算,丰富了干涉实验内容和光栅制作实验...     

全息、散班、云纹干涉法的Moiré几何原理

本文阐述了全息、散斑、云纹干涉法与Moiré几何理论的相似规律,用Moiré几何理论统一解释,比拟全息、散斑、云纹干涉法并给出相应的表达式。一、引言全息、     

基于莫尔理论的双波长全息干涉术分析

当用双波长全息干涉术通过单次曝光法或双曝光法对物体进行测量时 ,其效果相当于用一个等效波长λeq=λ1 λ2 /|λ1 -λ2 |对物体进行测量 ,扩大了测量波长的可选范围。采用莫尔理论从一个全新的角度对双波长全息干涉术的基本原理进行了分析和探讨 ,不仅揭示出了二者之间存在着的必然内在联系 ,而且还进一步证明了双波长全息干涉术的准确性和可行性 ,从而扩展了双波长全息干涉术的应用领域     

Geometric optics with atomic beams scattered by a detuned laser standing wave

We report on a theoretical and numerical study of the propagation of atomic beams crossing a detuned standing-wave laser beam in the geometric-optics limit. The interplay between the external and internal atomic degrees of freedom is used to manipulate the atomic motion along the light optical axis. By adjusting the atom–laser detuning, we demonstrate how to focus, split, and scatter atomic beams in real experiments. The novel effect of chaotic scattering of atoms on a regular near-resonant standing wave is found numerically and explained qualitatively. Some applications of the effects found are discussed.     

Loading of a krypton magneto-optical trap with two hollow laser beams in a Zeeman slower

A significant enhancement in the number of cold atoms in an atomic-beam-loaded magneto-optical trap (MOT) for metastable krypton atoms is observed when hollow laser beams are used in a Zeeman slower instead of a Gaussian laser beam. In the Zeeman slower setup, a combination of two hollow laser beams, i.e., a variable-diameter hollow beam generated using a pair of axicon lenses superimposed on a fixed-diameter hollow beam, has been used to reduce the longitudinal velocity of the atoms in the atomic beam below the capture speed of the MOT. The observed enhancement in the number of atoms in the MOT is attributed to reduced destruction of the atom cloud in the MOT and increased cooling of the off-axis atoms in the atomic beam, resulting from the use of hollow beams in the Zeeman slower.     

Fast-ion-beam laser probing of ion-source energy distributions and atomic structure

Collinear fast-ion-beam laser spectroscopy is a very high resolution probe for measuring ion-beam energy distributions and atomic structure parameters of interest in nuclear physics, atomic physics, and astrophysics. We have used offline 10-keV beams of atomic ions and a CW laser system to study the behavior of a Penning ion source and to measure hyperfine structure, isotope shifts, atomic lifetimes, spontaneous-emission branching fractions, oscillator strengths, and absolute wavelengths of a variety of atomic species from the lanthanide and transition-metal groups.     

Collimation of atomic beams by resonant laser radiation pressure

The application of the resonant light pressure created by an axially symmetrical light field for collimating atomic beams has been considered. As an example, consideration is given to the possibility of collimating an atomic beam by the light field produced by the reflection of a plane wave from the internal surface of a metal cone. It has been shown that the radiation pressure can reduce the atomic-beam transverse velocities to the value of the order of 100 cm/s which corresponds to effective temperature of about 10^–3 K. A method for producing collimated beams of cold atoms based on simultaneous deceleration and collimation of atomic beams by resonant laser radiation pressure is proposed.     

On the shape of absorption lines in a divergent atomic beam

The influence of the non-negligible width of the light beam on the shape of the spectral line observed in an atomic beam has been investigated theoretically. The expression obtained for the intensity distribution along the absorption line contour is studied for special cases of zinc and mercury atomic beams used in Fabry-Perot interferometry.     

Atom interferometers manipulated through the toroidal trap realized by the interference patterns of Laguerre-Gaussian beams

In this paper, we proposed new constructions of atom interferometers manipulated through the toroidal trap formed by the interference patterns of two co-propagation Laguerre-Gaussian (LG) beams. The coherent splitting and merging of the atomic ensemble, which is essential for the atom interferometer, is realized by the interference pattern of two LG beams. Along the beam propagation direction, a single-well trap is evolved into a double-well trap and then recombined back into a single-well trap, which can be used to form an atom interferometer.     

The enhanced nonlinear stimulated emission effect of an atomic beam by using an injection Fabry-Perot spherical cavity

When a high-intensity laser beam passes through a resonant atomic beam,non-linear stimulated emission effect will be produced.This effect can be enhanced up to two or-ders of magnitude by using an injection Fabry-Perot cavity.Experiments show that thismethod has high measuring contrast and high spectral resolution when it is used to measure thehyperfine absorption lines of atomic beams.     

Possible implementation of CNOT and CCNOT gates

The quantum optical gate CCNOT based on five level atomic scheme is discussed. The qubits are encoded in polarization properties of three optical beams. The nonlinear cross Kerr effect is used for getting nonlinear phase shifts in these beams. A way of CNOT implementation using coupled double quantum wells is suggested. The device is described in the framework of the model based on the operator extensions theory.     

Longitudinal ramsey-fringe spectroscopy in a calcium beam

For ultra-high resolution spectroscopic applications such as optical frequency standards, the value of thermal sources such as atomic beams is currently limited by secondorder Doppler broadening. The use of a longitudinal interaction geometry in which an atomic beam crosses the counter-propagating laser fields at a small angle is able to reduce second-order Doppler broadening to an insignificant level as well as to provide long interaction times without the necessity of large-diameter optical beams. We have analyzed this geometry for the case of the long-lived calcium intercombination line, and conclude that when combined with pulsed (Ramsey) excitation, the longitudinal interaction geometry could be used with a thermal calcium beam to create an optical frequency standard with a reproducibility of the order of 10^?14 for a few seconds averaging time. Our initial experimental results have demonstrated the first use of the longitudinal geometry.     

Sub-shot-noise high-sensitivity spectroscopy with optical parametric oscillator twin beams

Nondegenerate optical parametric oscillators generate above-threshold signal and idler beams that have intensity fluctuations correlated at the quantum level (twin beams). We describe what is to our knowledge the first high-sensitivity spectroscopy experiment using twin beams emitted by a cw optical parametric oscillator: a very weak two-photon absorption signal, in the 10(-7) range, is recorded on the 4S(1/2)-5S(1/2) transition of atomic potassium with a noise background that is reduced by 1.9 dB with respect to the shot-noise limit of the light used in the experiment.