Nav: Home

Using lasers to create ultra-short pulses

March 15, 2017

Physicists at Friedrich-Alexander Universität Erlangen-Nürnberg (FAU) have entered new territory with regard to the pulsing of electron beams. Their method could soon be used to develop electron microscopes suitable for ultra-short time scales such as needed for observing the motion of atoms.

Electron microscopes have opened up a whole new world to researchers: state-of-the-art scanning and transmission devices can now even image individual atoms. Despite achieving this enormously high resolution, operating with a constant electron beam has its disadvantages. Ultra-fast reactions, such as the breaking of chemical bonds or the vibrations of atoms, cannot be imaged with this method. Because of this problem, microscopes have been developed in recent years that use pulsed electron beams. 'This can be compared with a stroboscope which captures the movement of the test object using a rapid sequence of flashes,' explains Professor Peter Hommelhoff, Chair of Laser Physics at FAU. 'This principle has now been applied to electron pulses.'

Laser-controlled electrons

The particular challenge here is to generate pulses that are as short as possible - as electron 'packets' with shorter lengths reduce the time scale at which atomic movements can be imaged. By using a laser to manipulate a stream of electrons, they have succeeded in producing electron packets with a length of 1.3 femtoseconds -- a femtosecond is equivalent to one millionth of one billionth of a second. To achieve this, the physicists had to direct a beam of electrons over the surface of a silicon lattice, where they superimposed the optical field from laser pulses onto it in two sections. Dr. Martin Kozák, a member of Hommelhoff's team and primary author of the study, explains: 'We use the laser to control the frequency of the periodic field and synchronize it with the speed of the electrons. This allows the electrons to gain or lose energy, and we can generate ultra-short packets from a continuous beam.'

Pulses in the attosecond range possible

In addition to this controlled acceleration and deceleration, the FAU physicists have succeeded in laterally deflecting the electrons from an angled silicon lattice using laser pulses. The electrons are deflected in one direction or the other, depending on exactly when they interact with the laser field. This detection method is also used in streak cameras, which have already achieved resolutions in the femtosecond range. The method developed in Erlangen will actually achieve temporal resolutions in the attosecond range or a billionth of one billionth of a second. One application in which streak cameras are used is to observe the propagation of light.
-end-


University of Erlangen-Nuremberg

Related Electrons Articles:

Deceleration of runaway electrons paves the way for fusion power
Fusion power has the potential to provide clean and safe energy that is free from carbon dioxide emissions.
Shining light on low-energy electrons
The classic method for studying how electrons interact with matter is by analyzing their scattering through thin layers of a known substance.
Ultrafast nanophotonics: Turmoil in sluggish electrons' existence
An international team of physicists has monitored the scattering behavior of electrons in a non-conducting material in real-time.
NASA mission uncovers a dance of electrons in space
NASA's MMS mission studies how electrons spiral and dive around the planet in a complex dance dictated by the magnetic and electric fields, and a new study revealed a bizarre new type of motion exhibited by these electrons.
'Hot' electrons don't mind the gap
Rice University scientists discover that 'hot' electrons can create a photovoltage about a thousand times larger than ordinary temperature differences in nanoscale gaps in gold wires.
Electrons used to control ultrashort laser pulses
We may soon get better insight into the microcosm and the world of electrons.
Supercool electrons
Study of electron movement on helium may impact the future of quantum computing.
Two electrons go on a quantum walk and end up in a qudit
There is a variety of physical systems that can be used to implement a separate quantum bit, but significantly less research has been done into systems of several qubits or qudits.
Radiation that knocks electrons out and down, one after another
Researchers at Japan's Tohoku University are investigating novel ways by which electrons are knocked out of matter.
Controlling electrons in time and space
A new method has been developed to control electrons being emitted from metal tips.

Related Electrons Reading:

Pushing Electrons
by Daniel P. Weeks (Author)

Electron in Action
by Steve Kinney (Author)

Transmission Electron Microscopy: A Textbook for Materials Science (4 Vol set)
by David B. Williams (Author), C. Barry Carter (Author)

There Are No Electrons: Electronics for Earthlings
by Kenn Amdahl (Author)

Scanning Electron Microscopy and X-Ray Microanalysis
by Joseph I. Goldstein (Author), Dale E. Newbury (Author), Joseph R. Michael (Author), Nicholas W.M. Ritchie (Author), John Henry J. Scott (Author), David C. Joy (Author)

Pushing Electrons: A Guide for Students of Organic Chemistry, 3rd
by Daniel P. Weeks (Author)

Transmission Electron Microscopy: Diffraction, Imaging, and Spectrometry
by C. Barry Carter (Editor), David B. Williams (Editor)

Scanning Electron Microscopy and X-Ray Microanalysis: Third Edition
by Joseph Goldstein (Author), Dale E. Newbury (Author), David C. Joy (Author), Charles E. Lyman (Author), Patrick Echlin (Author), Eric Lifshin (Author), Linda Sawyer (Author), J.R. Michael (Author)

The Electron
by Dennis Morris (Author)

Interacting Electrons: Theory and Computational Approaches
by Richard M. Martin (Author), Lucia Reining (Author), David M. Ceperley (Author)

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Bias And Perception
How does bias distort our thinking, our listening, our beliefs... and even our search results? How can we fight it? This hour, TED speakers explore ideas about the unconscious biases that shape us. Guests include writer and broadcaster Yassmin Abdel-Magied, climatologist J. Marshall Shepherd, journalist Andreas Ekström, and experimental psychologist Tony Salvador.
Now Playing: Science for the People

#513 Dinosaur Tails
This week: dinosaurs! We're discussing dinosaur tails, bipedalism, paleontology public outreach, dinosaur MOOCs, and other neat dinosaur related things with Dr. Scott Persons from the University of Alberta, who is also the author of the book "Dinosaurs of the Alberta Badlands".