Name: experimental methods for spin- and angle-resolved photoemission spectroscopy combined with polarization-variable laser
Uploaded: 2018-06-28T13:00:00.000+00:00
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Description: Watch this Scientific Journal Video about Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser at JoVE.com

我们感谢 m. 中山, s. Toyohisa, 福岛和石田支持实验装置。我们感激地认识到, 通过26287061号项目和青年科学家 (b) 通过15K17675 项目的 Grantin (b) 为科学研究提供的资助。这项工作也得到日本下个 (创新领域 "拓扑材料科学", "16H00979 号") 和 jsp KAKENHI (批准号 16H02209) 的支持。

1. 装载和安装示例
<ol><li>将 Bi2Se313的单晶样品切成 1 x 1 x 0.5 毫米3 , 并使用银基环氧树脂将样品粘附在样品架上。</li>
	<li>将透明胶带粘贴到样品表面上。 注: 该透明胶带用于在超高真空 (特高压) 腔内切割样品以获得原子清洁的表面。</li>
	<li>将样品安装到负载锁的样品杂志中, 启动泵直到负载锁的压力低于 1×10-5宾夕法尼亚州。</li>
</ol>2. 试样裂解
<ol><li>打开负载锁和特高压准备室之间的特高压阀。</li>
	<li>使用连接到负载锁室的线性/旋转馈将样品杂志从负载岩石移动到准备室。</li>
	<li>从样品杂志上提取样品, 并附上准备室的转移杆。</li>
	<li>把样品杂志放回负载锁中, 关闭特高压阀门。</li>
	<li>等待, 直到准备室的压力低于 5×10-7宾夕法尼亚州</li>
	<li>在制备室中使用摆动棒剥离透明胶带, 在特高压条件下对试样进行切割。</li>
</ol>3. 样品转移到测量位置
<ol><li>将样品转移到特高压测量室, 并将试样固定在主 gonio 阶段, 由装有测量室的螺钉驱动。</li>
	<li>将 gonio 阶段移动到测量位置, 并使用千分尺阶段精确地将取样位置移到光谱仪的焦点上。</li>
</ol>4. 7 ev 激光装置
<ol><li>打开 Nd:YVO4 激光器。 注: 激光产生355纳米激光光, 重复率高120兆赫。</li>
	<li>打开激光光束快门, 确保激光穿过 KBBF 晶体, 产生 177 nm (6.994 eV) 的第二谐波波。</li>
	<li>通过改变355纳米激光与可变衰减器的功率, 优化 7 ev 激光器的功率。</li>
</ol>5. ARPES 数据采集
<ol><li>在台式计算机上打开分析器控制软件。 注: 我们使用 "SES 软件", 这是一个通用的程序控制 ScientaOmicron 分析仪与电子偏转器。</li>
	<li>在菜单栏上选择 "设置......" (图 2, 第一步 2-1)。</li>
	<li>选择ARPES 配置(图 3, 步骤 i. 3-1) 和ARPES 映射在列表中 (图 3, 第一步 3-2) 执行费米表面映射与光电子偏转器。</li>
	<li>单击 "编辑" (图 3, 第一步 3-3) 并配置费米曲面映射, 范围从-12°到12°的发射角θy 与0.5°的步长 (图 3, 第一步 3-4)。 注意: 用电子偏转器的半球分析器使我们能够映射费米表面而不进行样本旋转。</li>
	<li>单击 "运行" (图 2, 第一步 2-3)。</li>
</ol>6. SARPES 数据采集
<ol><li>手动更改 SARPES 测量的机器设置, 包括分析仪入口狭缝和孔径大小 (图 1)。</li>
	<li>在菜单栏上选择 "设置......" (图 2, 第一步 2-2)。</li>
	<li>选择 "旋转配置" (图 4、步骤 4-1) 和列表中的正常(图 4, 第一步 4-2), 然后单击"确定" (图 4, 第一步. 4-3)。</li>
	<li>选择DA30 (图 5, 第一步. 5-1) 在菜单栏和控制θ..。(图 5, 第一步. 5-2) 打开设置面板的 DA30 角 (θx, θy) 配置。</li>
	<li>选择发射角 (θx, θy) = (-6°, 0°) 以 SARPES 光谱 (图 5, 第一步. 5-3)。</li>
	<li>通过控制双极电容器库, 应用磁场, 将 VLEED 目标沿特定轴 (α: x、 y或z) 的正方向磁化。 注意: 在我们的系统中, 这个过程可以通过命令提示符完成 [图 6 (a)]。</li>
	<li>单击 "运行" 以采取强度频谱 (图 2, 第一步 2-3)。</li>
	<li>应用磁场对 VLEED 目标沿α方向磁化, 开始扫描以达到强度谱。</li>
	<li>计算自旋极化和自旋分辨谱。</li>
</ol>7. 扫描光极化依赖性
<ol><li>改变由步进电机精确控制的λ/2-waveplate 的角度来调节 7 eV 激光器的光极化。 注意: 在我们的系统中, 这个过程可以通过命令提示符完成 [图 6 (b)]。</li>
	<li>取x、y和z轴的自旋分辨光谱。</li>
	<li>将自旋分辨光谱扫描为光极化函数, 并将102°的半 waveplate 角与3°的步长大小变化。</li>
</ol>

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作者声明他们没有竞争的财政利益。

ARPES 和 SARPES 技术已被广泛用于研究电子带结构通过波段映射和自旋检测1,2。除了上述一般优点之外, 基于光偶极子激发的轨道选择规则的激光 SARPES 可以作为一种新的技术, 用于可视化波函数和量子自旋干涉中的自旋轨道耦合效应。.如图 9 和 10所示, 激光的偏振可以很容易地通过 waveplates 在p和s-偏振<sup cl...

角分辨光电子光谱学 (ARPES) 技术已发展成为研究固态1中准粒子带结构最有力的工具之一。ARPES 的最具吸引力的特征是在能量和动量空间中的电子态特征的波段映射能力。自旋解析 ARPES (SARPES), 这里装有自旋探测器, 即g。莫特探测器2,3, 进一步使我们能够解决的自旋特性的观测带结构4。由于莫特探测器可以测量两个轴 (x和z, 或y和z) 的旋转, 两个莫特探测器的组合进一步允许一个在三维度4,5 中获得旋转方向..然而, 几十年来, SARPES 实验的效率低 (通常是 1/10000, 与自旋集成 ARPES 测量相比)3,4,5,6 ,7, 它限制了能量和角分辨率。最近, SARPES 的能量分辨率增加了一个基于交换散射的高效自旋探测器, 所谓的极低能量电子衍射 (VLEED) 探测器7,8,9 ,10。利用该检测器, 数据质量得到了显著提高, 数据采集时间缩短。最近, SARPES 成功地解决了自旋极化电子态, 特别是自旋-轨道耦合效应, 导致了表面带7的自旋纹理。
在这里, 我们使用 SARPES 测量与偏振变真空紫外线激光 (激光 SARPES), 并证明了这一组合技术的巨大优势。通过对 Bi2Se3中自旋轨道耦合表面状态的研究, 提出了两种激光 SARPES 的能力。首先, 由于线性极化激光器在偶极过渡态中的轨道选择规律, p-和s-偏振光有选择地激发了不同轨道对称的特征波函数的一部分。这样的轨道选择性激发, 从而在 SARPES, 即轨道选择性 SARPES。其次, SARPES 中的三维 (3D) 自旋检测显示了自旋量子轴的方向, 直接显示了光极化依赖性的完整信息。在本议定书中, 我们简要描述了一种方法来执行这一最先进的激光 SARPES 技术来研究强自旋轨道耦合效应。
我们的激光 SARPES 系统位于11东京大学固体物理研究所。图 1显示了我们的激光 SAPRES 机的原理图。偏振变 7 eV 激光光12照亮样品表面, 光电子从样品中发出。激光偏振由 MgF2基λ/2-和λ/4 waveplates 自动控制, 选择性地使用线性和圆形偏振。半球电子分析仪纠正了光电子, 并分析了它们的动能 (E族) 和发射角 (θx 和θy)。在 CCD 摄像机监控的E型θx 屏幕上映射了光电子强度。该图像直接转化为互补空间的能量带结构。
对于 SARPES 测量, 通过电子分析仪分析的光电子具有特定的发射角和动能, 对两个具有90度光电子偏转器的 VLEED 型自旋探测器进行了导引, 光电子束聚焦在两个铁 (001)p(1×1) 薄膜的不同靶点由氧终止。通过在每个自旋探测器中使用一个 channeltron, 在单通道检测中检测到目标反射的光电子。VLEED 的目标可以磁化与亥姆霍兹型的电线圈, 这是安排与正交几何相互尊重。磁化方向由双极电容器库控制。双 VLEED 自旋探测器从而使我们能够分析三维光电子的自旋极化矢量。

<table><tbody><tr><td>DA30-L hemispherical analyzer</td><td>ScientaOmicron</td><td></td><td>http://www.scientaomicron.com/en/products/353/1170</td></tr><tr><td>Silver-based epoxy</td><td>Epoxy Technology</td><td>H20E</td><td></td></tr><tr><td>Sctoch tape</td><td>3M</td><td>801-1-18C</td><td></td></tr><tr><td>UHV valve</td><td>VAT</td><td>01034-KE01</td><td></td></tr><tr><td>linear/rotary feedthrough</td><td>Ferrovac</td><td>MD40</td><td></td></tr><tr><td>transfer rod</td><td>UHV design</td><td>PP series</td><td></td></tr><tr><td>wobble stick</td><td>Ferrovac</td><td>WM40</td><td></td></tr><tr><td>Paladin compact 355</td><td>Coherent</td><td></td><td></td></tr><tr><td>half waveplate</td><td>Kogakugiken</td><td></td><td>order made</td></tr><tr><td>Bipolar condenser bank</td><td>Tsuji electronics</td><td></td><td></td></tr></tbody></table>

experimental methods for spin- and angle-resolved photoemission spectroscopy combined with polarization-variable laser

本协议的目的是介绍如何执行自旋和角分辨光电子光谱与偏振-变 7-eV 激光器 (激光 SARPES), 并证明了这一技术的力量, 研究固体物理。激光 SARPES 达到两大功能。首先, 通过对线性极化激光器的轨道选择规律的研究, 可以在 SAPRES 实验中进行轨道选择性激励。其次, 该技术可以显示自旋量子轴作为光极化函数的变化的完整信息。为了演示这些能力在激光 SARPES 中的协作能力, 我们将此技术应用于对 Bi2Se3的自旋轨道耦合表面状态的研究。这种技术可以从自旋轨道耦合波函数中分解自旋和轨道元件。此外, 该技术作为利用直接自旋检测与偏振变量激光器协作的代表优势, 明确地直观地揭示了自旋量子轴在三维中的光极化依赖性。激光 SARPES 显著提高了光电子技术的能力。

在开始 SARPES 实验之前, 需要用高能量和角分辨率 (5.1-5.5) 的高度统计自旋综合 ARPES 结果准确地确定k位置, 以获得自旋分辨谱。图 7展示了双2Se3单晶的 ARPES 结果。这种材料被称为一个典型的拓扑绝缘体与自旋极化表面状态14,15。ARPES 带图清楚地解析了二维表面状态16?...

Watch this Scientific Journal Video about Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser at JoVE.com

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser

在这里, 我们将偏振变 7 eV 激光器与自旋-角分辨光电子技术相结合, 以可视化固态中的自旋轨道耦合效应。

自旋角分辨光电子光谱与偏振变激光相结合的实验方法

The goal of this protocol is to present how to perform spin- and angle-resolved photoemission spectroscopy combined with polarization-variable 7-eV laser ...

experimental-methods-for-spin-angle-resolved-photoemission

Research

JoVE Journal

Engineering

9.8K 次观看.  University of Tokyo. 在这里, 我们将偏振变 7 eV 激光器与自旋-角分辨光电子技术相结合, 以可视化固态中的自旋轨道耦合效应。

视频: Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (&omega;) and momentum (k) and the probability to find them in a particular state with given &omega; and k is described by the spectral function A(k, &omega;). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample.
In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He3 cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be determined with an unprecedented clarity.

The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.

在极低的温度下角分辨光电子能谱

The physical properties of a material are defined by its  electronic structure. Electrons in solids are characterized by energy (&omega;)  and momentum ...

科研

工程学

Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements

When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a new and inexpensive procedure to force mode locking in a pre-adjusted nonlinear polarization rotation fiber laser. This procedure is based on the detection of a sudden change in the output polarization state when mode locking occurs. This change is used to command the alignment of the intra-cavity polarization controller in order to find mode-locking conditions. More specifically, the value of the first Stokes parameter varies when the angle of the polarization controller is swept and, moreover, it undergoes an abrupt variation when the laser enters the mode-locked state. Monitoring this abrupt variation provides a practical easy-to-detect signal that can be used to command the alignment of the polarization controller and drive the laser towards mode locking. This monitoring is achieved by feeding a small portion of the signal to a polarization analyzer measuring the first Stokes parameter. A sudden change in the read out of this parameter from the analyzer will occur when the laser enters the mode-locked state. At this moment, the required angle of the polarization controller is kept fixed. The alignment is completed. This procedure provides an alternate way to existing automating procedures that use equipment such as an optical spectrum analyzer, an RF spectrum analyzer, a photodiode connected to an electronic pulse-counter or a nonlinear detecting scheme based on two-photon absorption or second harmonic generation. It is suitable for lasers mode locked by nonlinear polarization rotation. It is relatively easy to implement, it requires inexpensive means, especially at a wavelength of 1550 nm, and it lowers the production and operation costs incurred in comparison to the above-mentioned techniques.

A protocol to detect and automate mode locking in a pre-adjusted nonlinear polarization rotation fiber laser is presented. The detection of a sudden change in the output polarization state when mode locking occurs is used to command the alignment of an intra-cavity polarization controller in order to find mode-locking conditions.

锁模自动化的非线性偏振旋转光纤激光器通过输出偏振测量

When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a ...

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy

High resolution optical spectroscopy methods are demanding in terms of either technology, equipment, complexity, time or a combination of these. Here we demonstrate an optical spectroscopy method that is capable of resolving spectral features beyond that of the spin fine structure and homogeneous linewidth of single quantum dots (QDs) using a standard, easy-to-use spectrometer setup. This method incorporates both laser and photoluminescence spectroscopy, combining the advantage of laser line-width limited resolution with multi-channel photoluminescence detection. Such a scheme allows for considerable improvement of resolution over that of a common single-stage spectrometer. The method uses phonons to assist in the measurement of the photoluminescence of a single quantum dot after resonant excitation of its ground state transition. The phonon&#39;s energy difference allows one to separate and filter out the laser light exciting the quantum dot. An advantageous feature of this method is its straight forward integration into standard spectroscopy setups, which are accessible to most researchers.

The manuscript describes a method of phonon-assisted quasi-resonant fluorescence spectroscopy that incorporates both laser-limited resolution and photoluminescence (PL) spectroscopy. This method utilizes optical phonons to provide linewidth-limited resolution spectra of atom-like semiconductor structures in the energy domain. The method is also easily realized with a single spectrometer optical spectroscopy setup.

高分辨率声子辅助准共振荧光光谱仪

High resolution optical spectroscopy methods are demanding in terms of either technology, equipment, complexity, time or a combination of these. Here we ...

Direct Imaging of Laser-driven Ultrafast Molecular Rotation

We present a method for visualizing laser-induced, ultrafast molecular rotational wave packet dynamics. We have developed a new 2-dimensional Coulomb explosion imaging setup in which a hitherto-impractical camera angle is realized. In our imaging technique, diatomic molecules are irradiated with a circularly polarized strong laser pulse. The ejected atomic ions are accelerated perpendicularly to the laser propagation. The ions lying in the laser polarization plane are selected through the use of a mechanical slit and imaged with a high-throughput, 2-dimensional detector installed parallel to the polarization plane. Because a circularly polarized (isotropic) Coulomb exploding pulse is used, the observed angular distribution of the ejected ions directly corresponds to the squared rotational wave function at the time of the pulse irradiation. To create a real-time movie of molecular rotation, the present imaging technique is combined with a femtosecond pump-probe optical setup in which the pump pulses create unidirectionally rotating molecular ensembles. Due to the high image throughput of our detection system, the pump-probe experimental condition can be easily optimized by monitoring a real-time snapshot. As a result, the quality of the observed movie is sufficiently high for visualizing the detailed wave nature of motion. We also note that the present technique can be implemented in existing standard ion imaging setups, offering a new camera angle or viewpoint for the molecular systems without the need for extensive modification.

We present a protocol for creating a real-time movie of a molecular rotational wave packet using a high-resolution Coulomb explosion imaging setup.

激光驱动的超快分子旋转直接成像

We present a method for visualizing laser-induced, ultrafast molecular rotational wave packet dynamics. We have developed a new 2-dimensional Coulomb ...

化学

Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons

We have developed a unique method to measure the excitation and coupling rates between the light emitters and surface plasmon polaritons (SPPs) arising from metallic periodic arrays without involving time-resolved techniques. We have formulated the rates by quantities that can be measured by simple optical measurements. The instrumentation based on angle- and polarization-resolved reflectivity and photoluminescence spectroscopy will be described in detail here. Our approach is intriguing due to its simplicity, which requires routine optics and several mechanical stages, and thus is highly affordable to most of the research laboratories.

This protocol describes the instrumentation for determining the excitation and coupling rates between light emitters and Bloch-like surface plasmon polaritons arising from periodic arrays.

光发射器与表面等离子体极化激元的激发和耦合速率的测定

We have developed a unique method to measure the excitation and coupling rates between the light emitters and surface plasmon polaritons (SPPs) arising ...

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F&#8722;

Anion photoelectron imaging is a very efficient method for the study of energy states of bound negative ions, neutral species and interactions of unbound electrons with neutral molecules/atoms. State-of-the-art in vacuo anion generation techniques allow application to a broad range of atomic, molecular, and cluster anion systems. These are separated and selected using time-of-flight mass spectrometry. Electrons are removed by linearly polarized photons (photo detachment) using table-top laser sources which provide ready access to excitation energies from the infra-red to the near ultraviolet. Detecting the photoelectrons with a velocity mapped imaging lens and position sensitive detector means that, in principle, every photoelectron reaches the detector and the detection efficiency is uniform for all kinetic energies. Photoelectron spectra extracted from the images via mathematical reconstruction using an inverse Abel transformation reveal details of the anion internal energy state distribution and the resultant neutral energy states. At low electron kinetic energy, typical resolution is sufficient to reveal energy level differences on the order of a few millielectron-volts, i.e., different vibrational levels for molecular species or spin-orbit splitting in atoms. Photoelectron angular distributions extracted from the inverse Abel transformation represent the signatures of the bound electron orbital, allowing more detailed probing of electronic structure. The spectra and angular distributions also encode details of the interactions between the outgoing electron and the residual neutral species subsequent to excitation. The technique is illustrated by the application to an atomic anion (F&#8722;), but it can also be applied to the measurement of molecular anion spectroscopy, the study of low lying anion resonances (as an alternative to scattering experiments) and femtosecond (fs) time resolved studies of the dynamic evolution of anions.

Here, we present a protocol for photoelectron imaging of anionic species. Anions generated in vacuo and separated by mass spectrometry are probed using velocity mapped photoelectron imaging, providing details of anion and neutral energy levels, anion and neutral structure and the nature of the anion electronic state.

由 F− 310 Nm 支队所示的阴离子光电子成像

Anion photoelectron imaging is a very efficient method for the study of energy states of bound negative ions, neutral species and interactions of unbound ...

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference

We present a high-performance source of unconditional polarization-entangled photons that have a high-emission rate, a broadband distribution, are degenerated and postselection free. The property of the source is based on the multiple quantum interference effect with a round-trip configuration of a Sagnac interferometer. The quantum interference effects make it possible to use the high generation efficiency of the polarization-entangled photons to process parametric down-conversion, and separate degenerated photon pairs into different optical modes without a postselection requirement. The principle of the optical system was described and experimentally used to measure the fidelity and Bell parameters, and also to characterize the generated polarization-entangled photons from a minimum of six combinations of polarization correlated data. The experimentally obtained fidelity and Bell parameters exceeded the classical local correlation limit and are clear evidence of the generation of unconditional polarization-entangled photons.

We describe an optical system for the generation of unconditional polarization-entangled photons based on multiple quantum interference effects with a detection scheme to estimate the experimental fidelity of generated entangled photons.

基于多重量子干扰生成无条件极化纠缠光子的光子系统

We present a high-performance source of unconditional polarization-entangled photons that have a high-emission rate, a broadband distribution, are ...

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures

Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by local enhancement of electric field intensity that strengthens light-matter interactions, enabling applications such as surface-enhanced Raman scattering (SERS) and surface plasmon enhanced sensing. In the presence of magneto-optically active materials, the local field enhancement gives rise to anomalous magneto-optical activity. Typically, the confined modes of a given photonic crystal depend strongly on the wavelength and incidence angle of the incident electromagnetic radiation. Thus, spectral and angular-resolved measurements are needed to fully identify them as well as to establish their relationship with the magneto-optical activity of the crystal. In this article, we describe how to use a Fourier-plane (back focal plane) microscope to characterize magneto-optically active samples. As a model system, here we use a plasmonic grating built out of magneto-optically active Au/Co/Au multilayer. In the experiments, we apply a magnetic field on the grating in situ and measure its reciprocal space response, obtaining the magneto-optical response of the grating over a range of wavelengths and incident angles. This information enables us to build a complete map of the plasmonic band structure of the grating and the angle and wavelength dependent magneto-optical activity. These two images allow us to pinpoint the effect that the plasmon resonances have on the magneto-optical response of the grating. The relatively small magnitude of magneto-optical effects requires a careful treatment of the acquired optical signals. To this end, an image processing protocol for obtaining magneto-optical response from the acquired raw data is laid out.

Photonic band structure enables understanding how confined electromagnetic modes propagate within a photonic crystal. In photonic crystals that incorporate magnetic elements, such confined and resonant optical modes are accompanied by enhanced and modified magneto-optical activity. We describe a measurement procedure to extract the magneto-optical band structure by Fourier space microscopy.

光子纳米结构的光谱和角度解析磁-光学特性

Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by ...

In Situ Measurement of Vacuum Window Birefringence using 25Mg+ Fluorescence

Accurate control of the polarization states of laser light is important in precision measurement experiments. In experiments involving the use of a vacuum environment, the stress-induced birefringence effect of the vacuum windows will affect the polarization states of laser light inside the vacuum system, and it is very difficult to measure and optimize the polarization states of the laser light in situ. The purpose of this protocol is to demonstrate how to optimize the polarization states of the laser light based on the fluorescence of ions in the vacuum system, and how to calculate the birefringence of vacuum windows based on azimuthal angles of external wave plates with Mueller matrix. The fluorescence of 25Mg+ ions induced by laser light that is resonant with the transition of |32P3/2,F = 4, mF&#160;= 4<img align="center" alt="Equation 100" src="/files/ftp_upload/61175/61175img1.jpg" style="color: rgb(68, 0, 68); font-size: 18px; font-weight: 700;" />&#160;&#8594;&#160;|32S1/2,F = 3, mF&#160;= 3<img align="center" alt="Equation 100" src="/files/ftp_upload/61175/61175img1.jpg" style="color: rgb(68, 0, 68); font-size: 18px; font-weight: 700;" />&#160;is sensitive to the polarization state of the laser light, and maximum fluorescence will be observed with pure circularly polarized light. A combination of half-wave plate (HWP) and quarter-wave plate (QWP) can achieve arbitrary phase retardation and is used for compensating the birefringence of the vacuum window. In this experiment, the polarization state of the laser light is optimized based on the fluorescence of 25Mg+ ion with a pair of HWP and QWP outside the vacuum chamber. By adjusting the azimuthal angles of the HWP and QWP to obtain maximum ion fluorescence, one can obtain a pure circularly polarized light inside the vacuum chamber. With the information on the azimuthal angles of the external HWP and QWP, the birefringence of the vacuum window can be determined.

In Situ Measurement of Vacuum Window Birefringence using 25Mg+ Fluorescence

Presented here is a method to measure the birefringence of vacuum windows by maximizing the fluorescence counts emitted by Doppler cooled 25Mg+ ions in an ion trap. The birefringence of vacuum windows will change the polarization states of the laser, which can be compensated by changing the azimuthal angles of external wave plates.

使用 25Mg + 荧光对真空窗双参考进行 原点测量

Accurate control of the polarization states of laser light is important in precision measurement experiments. In experiments involving the use of a vacuum ...

使用偏振敏感双光子显微镜表征球晶

Polarization-Sensitive Two-Photon Microscopy for a Label-Free Amyloid Structural Characterization

Compared to its one-photon counterpart, two-photon excitation is beneficial for bioimaging experiments because of its lower phototoxicity, deeper tissue penetration, efficient operation in densely packed systems, and reduced angular photoselection of fluorophores. Thus, the introduction of polarization analysis in two-photon fluorescence microscopy (2PFM) provides a more precise determination of molecular organization in a sample compared to standard imaging methods based on linear optical processes. In this work, we focus on polarization-sensitive 2PFM (ps-2PFM) and its application in the determination of molecular ordering within complex bio-structures-amyloid spherulites. Neurodegenerative diseases such as Alzheimer's or Parkinson's are often diagnosed through the detection of amyloids-protein aggregates formed due to an impaired protein misfolding process. Exploring their structure leads to a better understanding of their creation pathway and consequently, to developing more sensitive diagnostic methods. This paper presents the ps-2PFM adapted for the determination of local fibril ordering inside the bovine insulin spherulites and spherical amyloidogenic protein aggregates. Moreover, we prove that the proposed technique can resolve the three-dimensional organization of fibrils inside the spherulite.

作者聚焦:使用偏振敏感双光子显微镜对复杂生物结构进行无创成像 

This paper describes how polarization-sensitive two-photon microscopy could be applied to characterize the local organization within label-free amyloid superstructures-spherulites. It also describes how to prepare and measure the sample, assemble the required setup, and analyze the data to obtain information about the local organization of amyloid fibrils.

偏振敏感双光子显微镜用于无标记淀粉样蛋白结构表征

Compared to its one-photon counterpart, two-photon excitation is beneficial for bioimaging experiments because of its lower phototoxicity, deeper tissue ...

自旋角分辨光电子光谱与偏振变激光相结合的实验方法

摘要

探索更多视频

此视频中的章节

在极低的温度下角分辨光电子能谱

锁模自动化的非线性偏振旋转光纤激光器通过输出偏振测量

高分辨率声子辅助准共振荧光光谱仪

激光驱动的超快分子旋转直接成像

光发射器与表面等离子体极化激元的激发和耦合速率的测定

由 F⁻ 310 Nm 支队所示的阴离子光电子成像

基于多重量子干扰生成无条件极化纠缠光子的光子系统

光子纳米结构的光谱和角度解析磁-光学特性

使用 ²⁵Mg + 荧光对真空窗双参考^进行原点测量

偏振敏感双光子显微镜用于无标记淀粉样蛋白结构表征

自旋角分辨光电子光谱与偏振变激光相结合的实验方法

摘要

探索更多视频

此视频中的章节

在极低的温度下角分辨光电子能谱

锁模自动化的非线性偏振旋转光纤激光器通过输出偏振测量

高分辨率声子辅助准共振荧光光谱仪

激光驱动的超快分子旋转直接成像

光发射器与表面等离子体极化激元的激发和耦合速率的测定

由 F− 310 Nm 支队所示的阴离子光电子成像

基于多重量子干扰生成无条件极化纠缠光子的光子系统

光子纳米结构的光谱和角度解析磁-光学特性

使用 25Mg + 荧光对真空窗双参考进行 原点测量

偏振敏感双光子显微镜用于无标记淀粉样蛋白结构表征

由 F⁻ 310 Nm 支队所示的阴离子光电子成像

使用 ²⁵Mg + 荧光对真空窗双参考^进行原点测量