Sluggish electrons caught in action
By creating and using the first optical attosecond pulse, scientists from LMU and MPQ measured the time it takes electrons inside atoms to respond to the electromagnetic forces of light.
In the race to establish ever-faster electronics, light could play an important role. For instance, using light pulses of a precisely controlled waveform, physicists aim to switch electric currents in electronics circuits with light frequencies. But will electrons in such circuits follow light oscillations instantaneously? How fast will electrons react to the push of a “light-based” button? Or, from a more fundamental perspective: how fast do electrons bound in atoms, molecules or solids respond to light? Now, an international collaboration of physicists led by Dr. Eleftherios Goulielmakis and Ferenc Krausz, Head of the Institute of Experimental Physics at LMU Munich and Director at the Max Planck Institute for Quantum Optics (MPQ), and researchers from Texas A&M University, USA, and the Lomonosov Moscow State University, have been able to track the effect of this delay for the first time.
By creating the first optical attosecond pulse and using it to set electrons in krypton atoms in motion, they discovered that it takes as long as 100 attoseconds for electrons to respond to the electromagnetic forces of light. “Our study closes a several-decades-long inquiry into the fundamental dynamic response of matter to light fields. From the rotation and the nuclear motion in molecules captured in the last decades with femtosecond technology, we are now able for the first time to track in real time the response of electrons bound in atoms,” Goulielmakis, head of the research group “Attoelectronics” at the Max Planck Institute of Quantum Optics, pointed out. (MPQ/LMU)