The study, published in Nature Physics, focused on extremely short laser pulses, less than 10 femtoseconds long - a femtosecond is one million-billionth of a second. These laser pulses can allow scientists to move and control the electrons in atoms and molecules, and to understand, for example, how molecules are formed. To achieve this reliably, the pulse of electromagnetic waves emitted from the laser must be controlled and measured with a precision which, until now, has been very hard to achieve.
The team of physicists from Imperial College London attained an unprecedented level of accurate measurement by firing the femtosecond laser pulse into a sample of gas, which responds by emitting an x-ray pulse which is even shorter in duration - up to 10 times shorter than the original laser pulse. The researchers found that the spectrum of the x-ray pulse has encoded within it all the information necessary to precisely reconstruct the waveform of the original laser pulse. Through careful measurements and some 'intelligent' software designed specifically for this purpose, the researchers were therefore able, for the first time, to measure the waveform of individual femtosecond pulses.
Dr John Tisch, one of the Imperial research team, said: "This measurement technique is so accurate that we can determine the position of a peak in the pulse of electromagnetic waves from the laser with a precision of a mere 0.05 femtoseconds - in other words, 50 attoseconds. Also, the measurement can be made on individual pulses rather than by looking at the average properties of many pulses, so this is an important step forwards."
Dr Tisch explains that not only will this new technique lead to a greater ability to use short laser pulses for accurate sub-atomic level research, but it also sheds new light on the extremely short x-ray pulses emitted in response: "The x-ray pulses we used in the measurement process of our research are of great interest in their own right," he says. "They are on the attosecond timescale, which is even shorter than a femtosecond - just one billion-billionth of a second. They are a new tool for scientists to probe even faster motion than the femtosecond pulses that triggered them."
The research team have recently received a four-year £2.5 million grant from the EPSRC to take this research to the next stage. Professor Jonathan Marangos explains: "Now we've perfected this technique, we are going to look into using our accurate measurements and control of these lasers to manipulate electrons and control quantum processes."
Laura Gallagher | EurekAlert!
Unraveling the nature of 'whistlers' from space in the lab
15.08.2018 | American Institute of Physics
Early opaque universe linked to galaxy scarcity
15.08.2018 | University of California - Riverside
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur
What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...
08.08.2018 | Event News
27.07.2018 | Event News
25.07.2018 | Event News
15.08.2018 | Physics and Astronomy
15.08.2018 | Earth Sciences
15.08.2018 | Physics and Astronomy