Stimulated excitation electron microscopy and spectroscopy
1Department of Physics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, UK.
Ultramicroscopy
|October 15, 2014
Summary
New electron optics and spectroscopy methods allow studying ultra-low energy excitations like phonons. Near-field theory analyzes these, enabling phonon mapping and imaging for advanced materials analysis.
Area of Science:
- Electron optics and spectroscopy
- Materials science
- Condensed matter physics
Background:
- Instrumentation advances enable exploring ultra-low energy excitations.
- Phonons, bond vibrations, and Johnson noise are key areas of interest.
- Excitations can be induced by various sources, including fast electrons, thermal energy, and radiation.
Purpose of the Study:
- To explore ultra-low energy excitations using advanced electron optics and spectroscopy.
- To analyze excitation processes using near-field theory.
- To discuss possibilities for phonon mapping and imaging.
Main Methods:
- Utilizing near-field theory for electron energy loss and gain analysis.
- Investigating excitation mechanisms beyond fast electrons (thermal, radiation).
- Considering atomic resolution structure imaging and diffraction contrast imaging.
Main Results:
- Near-field theory offers a framework for analyzing ultra-low energy excitations.
- Phonon mapping and imaging are potential applications.
- Observable effects in atomic resolution and diffraction contrast imaging are expected.
Conclusions:
- Advanced electron techniques open new avenues for studying fundamental material properties.
- Near-field theory is crucial for understanding these low-energy phenomena.
- Future research directions include single atom recoil transitions and laser-boosted signals.
Related Concept Videos
01:25Overview of Electron Microscopy
11.6K
The wavelengths of visible light ultimately limit the maximum theoretical resolution of images created by light microscopes. Most light microscopes can only magnify 1000X, and a few can magnify up to 1500X. Electrons, like electromagnetic radiation, can behave like waves, but with wavelengths of 0.005 nm, they produce significantly greater resolution up to 0.05 nm as compared to 500 nm for visible light. An electron microscope (EM) can create a sharp image that is magnified up to 2,000,000X.
11.6K
01:07Scanning Electron Microscopy
5.1K
A scanning electron microscope (SEM) is used to study the surface features of a sample by using an electron beam that scans the sample surface in a two-dimensional manner. Typically, areas between ~1 centimeter to 5 micrometers in width can be imaged. SEM can be used to image bacteria, viruses, tissues as well as larger samples like insects. Conventional SEM gives a magnification ranging from 20X to 30,000X and spatial resolution of 50 to 100 nanometers.
Fundamental Principles
Accelerated...
Fundamental Principles
Accelerated...
5.1K
01:15Transmission Electron Microscopy
6.0K
In 1931, physicist Ernst Ruska—building on the idea that magnetic fields can direct an electron beam just as lenses can direct a beam of light in an optical microscope—developed the first prototype of the electron microscope. This development led to the development of the field of electron microscopy. In the transmission electron microscope (TEM), electrons are produced by a hot tungsten element and accelerated by a potential difference in an electron gun, which gives them up to 400...
6.0K
01:22Atomic Emission Spectroscopy: Instrumentation
1.5K
The instrumentation of atomic emission spectrometry (AES) involves various components, including atomization devices that convert samples into gas-phase atoms and ions. There are two main types of atomization devices: continuous and discrete atomizers. Continuous atomizers, like plasmas and flames, introduce samples in a constant stream, while discrete atomizers inject individual samples using syringes or autosamplers. The most common discrete atomizer is the electrothermal atomizer.
1.5K
01:37Super-resolution Fluorescence Microscopy
12.2K
Super-resolution fluorescence microscopy (SRFM) provides a better resolution than conventional fluorescence microscopy by reducing the point spread function (PSF). PSF is the light intensity distribution from a point that causes it to appear blurred. Due to PSF, each fluorescing point appears bigger than its actual size, and it is the PSF interference of nearby fluorophores that causes the blurred image. Various approaches to achieving higher resolution through SRFM have recently been...
12.2K
01:20Atomic Emission Spectroscopy: Overview
3.0K
Atomic emission spectroscopy (AES) is an analytical technique used to determine the elemental composition of a sample by analyzing the light emitted from excited atoms. In AES, atoms in a sample are excited to higher energy levels by thermal energy from high-temperature sources, such as plasma, arcs, or sparks. When these excited atoms return to lower energy states, they emit light at specific wavelengths characteristic of each element. The resulting atomic emission spectrum, which consists of...
3.0K