Attosecond 'lighthouses': A simple method for generating isolated ultrashort pulses

Nov 30, 2012

Electrons move extremely rapidly inside atoms and molecules (the order of magnitude is the attosecond, i.e. 10-18 of a second). One way to observe these phenomena is to use isolated ultrashort pulses of light, which are successfully characterized at this time scale. As demonstrated by researchers at CEA-IRAMIS and the Applied Optics Laboratory (LOA, CNRS/ENSTA-Paris Tech/École Polytechnique), there is a particularly well-adapted light source that can be used to carry out such research into how matter behaves. The results are published in Nature Photonics on December 1, 2012.

To observe the extremely rapid motion of in the core of atoms and molecules we require pulses in the attosecond range, allowing us to carry out "pump-probe" experiments in which an initial pulse excites the system, and a second allows us to observe the effect of this excitation, following a variable time delay.

The current method and its limitations

It is not possible to generate the kind of pulse required using standard laser optics technology. Until now, the only method that has been demonstrated to achieve such short lengths of time, utilizes the interaction between ultra-intense (10-15 s) and matter: as it interacts with the target, this pulse is deformed, producing a train of pulses of the order of a few tens of attoseconds each. These pulses follow each other at extremely short intervals, making them difficult to use in experiments, and, over the last ten years or so, various methods for generating an isolated attosecond pulse have been suggested.

Innovative approach of this study

To produce isolated attosecond pulses, the scientists came up with the much simpler and more easily exploitable idea of spatially scattering the train of pulses, just like the from a lighthouse. Each attosecond pulse is thus emitted in a slightly different direction, giving a series of attosecond pulses that are clearly distinct in terms of the direction in which they propagate.

At a distance from the solid target, the successive attosecond pulses are distinct and, since they are several millimeters apart, can be isolated from one another.

The principle behind this new approach, initially put forward by the team at IRAMIS, was first validated theoretically by numerical simulation, using France's HPC facility, GENCI (Grand équipement national de calcul intensif). The experimental demonstration was then performed at LOA, the Laboratory (École Polytechnique-CNRS-ENSTA-ParisTech) on a laser chain delivering pulses close to the ultrashort optical cycle, thanks to very close collaboration between the two laboratories.

The effect observed opens up a world of new possibilities for attosecond science, a new science that has developed rapidly in the last 10 years. Using a single laser pulse to generate a number of isolated attosecond pulses, in the form of perfectly synchronous beams at distinct angles, the attosecond "lighthouses" are the ideal for future pump-probe experiments designed for studying electronic motion in mater.

Explore further: 'Dressed' laser aimed at clouds may be key to inducing rain, lightning

add to favorites email to friend print save as pdf

Related Stories

Flashes of light out of the mirror

Jun 12, 2012

( -- A team of the Laboratory of Attosecond physics at the Max Planck Institute of Quantum Optics developed an alternative way of generating attosecond flashes of light. 

K-State attosecond research could aid Homeland Security

May 21, 2007

Building a new laser-like X-ray source powerful and quick enough to capture fast motion in the atomic world is a big job. But Zenghu Chang, Kansas State University professor of physics, and his team of physicists and engineers ...

Recommended for you

Robotics goes micro-scale

Apr 17, 2014

( —The development of light-driven 'micro-robots' that can autonomously investigate and manipulate the nano-scale environment in a microscope comes a step closer, thanks to new research from the ...

High power laser sources at exotic wavelengths

Apr 14, 2014

High power laser sources at exotic wavelengths may be a step closer as researchers in China report a fibre optic parametric oscillator with record breaking efficiency. The research team believe this could ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

2.3 / 5 (3) Dec 01, 2012
Nice, but obvious!

More news stories

Could 'Jedi Putter' be the force golfers need?

Putting is arguably the most important skill in golf; in fact, it's been described as a game within a game. Now a team of Rice engineering students has devised a training putter that offers golfers audio, ...

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.