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:

Plasma electrons can be used to produce metallic films
Computers, mobile phones and all other electronic devices contain thousands of transistors, linked together by thin films of metal.
Flatter graphene, faster electrons
Scientists from the Swiss Nanoscience Institute and the Department of Physics at the University of Basel developed a technique to flatten corrugations in graphene layers.
Researchers develop one-way street for electrons
The work has shown that these electron ratchets create geometric diodes that operate at room temperature and may unlock unprecedented abilities in the illusive terahertz regime.
Photons and electrons one on one
The dynamics of electrons changes ever so slightly on each interaction with a photon.
Using light to put a twist on electrons
Method with polarized light can create and measure nonsymmetrical states in a layered material.
What if we could teach photons to behave like electrons?
The researchers tricked photons - which are intrinsically non-magnetic - into behaving like charged electrons.
Electrons in rapid motion
Researchers observe quantum interferences in real-time using a new extreme ultra-violet light spectroscopy technique.
Taming electrons with bacteria parts
In a new study, scientists at the MSU-DOE Plant Research Laboratory report a new synthetic system that could guide electron transfer over long distances.
Hot electrons harvested without tricks
Semiconductors convert energy from photons into an electron current. However, some photons carry too much energy for the material to absorb.
Cooling nanotube resonators with electrons
In a study in Nature Physics, ICFO researchers report on a technique that uses electron transport to cool a nanomechanical resonator near the quantum regime.
More Electrons News and Electrons Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Our Relationship With Water
We need water to live. But with rising seas and so many lacking clean water – water is in crisis and so are we. This hour, TED speakers explore ideas around restoring our relationship with water. Guests on the show include legal scholar Kelsey Leonard, artist LaToya Ruby Frazier, and community organizer Colette Pichon Battle.
Now Playing: Science for the People

#568 Poker Face Psychology
Anyone who's seen pop culture depictions of poker might think statistics and math is the only way to get ahead. But no, there's psychology too. Author Maria Konnikova took her Ph.D. in psychology to the poker table, and turned out to be good. So good, she went pro in poker, and learned all about her own biases on the way. We're talking about her new book "The Biggest Bluff: How I Learned to Pay Attention, Master Myself, and Win".
Now Playing: Radiolab

Uncounted
First things first: our very own Latif Nasser has an exciting new show on Netflix. He talks to Jad about the hidden forces of the world that connect us all. Then, with an eye on the upcoming election, we take a look back: at two pieces from More Perfect Season 3 about Constitutional amendments that determine who gets to vote. Former Radiolab producer Julia Longoria takes us to Washington, D.C. The capital is at the heart of our democracy, but it's not a state, and it wasn't until the 23rd Amendment that its people got the right to vote for president. But that still left DC without full representation in Congress; D.C. sends a "non-voting delegate" to the House. Julia profiles that delegate, Congresswoman Eleanor Holmes Norton, and her unique approach to fighting for power in a virtually powerless role. Second, Radiolab producer Sarah Qari looks at a current fight to lower the US voting age to 16 that harkens back to the fight for the 26th Amendment in the 1960s. Eighteen-year-olds at the time argued that if they were old enough to be drafted to fight in the War, they were old enough to have a voice in our democracy. But what about today, when even younger Americans are finding themselves at the center of national political debates? Does it mean we should lower the voting age even further? This episode was reported and produced by Julia Longoria and Sarah Qari. Check out Latif Nasser's new Netflix show Connected here. Support Radiolab today at Radiolab.org/donate.