Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Capturing electrons in action

A technique for characterizing ultrafast light pulses will lead to better optical probes for studying electron dynamics

Scientists at RIKEN have developed a way to measure the wavelike properties of ultrafast (attosecond) light pulses—an important step toward being able to probe the dynamics of electrons, atoms and molecules.

Quantum mechanics theory can completely describe the structure of atoms and molecules. But directly observing electronic motion in an atom requires a technique that can take snapshots of the electron on time scales of less than a femtosecond (10-15 s). To this end, scientists are working to generate ultraviolet light pulses that are only 10–100 attoseconds (10-18 s) long.

Electrons, like light, have wavelike properties. Thus, when a fast optical pulse—or sequence of pulses—interacts with the electrons in an atom, it creates an interference pattern that can effectively image the electron over time.

The challenge is to create a sequence, or ‘train’, of pulses, each with the same, well-defined wavelike properties. For this reason, the technique developed by Yasuo Nabekawa and colleagues at the RIKEN Advanced Science Institute in Wako allows them to compare consecutive pulses in an attosecond light pulse series1.

“Ultimately, the goal of our research is to control atoms and molecules with the attosecond pulse train,” says Nabekawa.

To produce the attosecond pulses, the team started with a series of intense laser-generated ultraviolet light pulses, each approximately 40 femtoseconds in duration. When the laser pulses interacted with a gas of xenon atoms, they generated pulses of light with odd integer (1, 3, 5, etc…) multiples of the frequency of the original laser pulse. These higher frequency pulses—or, ‘harmonics’—reached into the attosecond range.

Detecting ultrafast motion in atoms and molecules requires that the pulses in the train are ‘coherent’ with each other, meaning they are in phase, similar to soldiers marching in lock-step. The team therefore designed its experiment specifically to determine the coherence between the pulses in each of the higher harmonics.

Spatially separating the harmonics allowed the team to measure the coherence between pulses of each harmonic individually. Each harmonic was then split into two beams that traveled down a long arm, before being recombined (Fig. 1). A CCD camera measured the interference pattern between the recombined beams, which provides a measure of the coherence between pulses.

While the current measurements relate to characterizing the optical pulse itself, the RIKEN team plans to build upon these experiments to study ionization and dissociation of electrons from atoms and molecules.


1. Nabekawa, Y., Shimizu, T., Furukawa,Y., Takahashi, E.J. & Midorikawa, K. Interferometry of attosecond pulse trains in the extreme ultraviolet wavelength region. Physical Review Letters 102, 213904 (2009).

The corresponding author for this highlight is based at the RIKEN Intense Attosecond Pulse Research Team

Saeko Okada | Research asia research news
Further information:

More articles from Power and Electrical Engineering:

nachricht Fluorescent holography: Upending the world of biological imaging
25.10.2016 | Colorado State University

nachricht Did you know that infrared heating is an essential part of automotive manufacture?
25.10.2016 | Heraeus Noblelight GmbH

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

3-D-printed structures shrink when heated

26.10.2016 | Materials Sciences

Indian roadside refuse fires produce toxic rainbow

26.10.2016 | Health and Medicine

First results of NSTX-U research operations

26.10.2016 | Physics and Astronomy

More VideoLinks >>>