Scientists working in optics labs often use lasers to change the properties of matter. But because they occur on the timescale of attoseconds―one-billionth of one‑billionth of a second―the induced changes are difficult to observe and analyze. Now, Weizmann physicists have invented a powerful method for measuring how pulsed laser light modifies the refractive properties of matter, that is, the way light slows down as it passes through a particular material.
This new approach may lead to the development of technologies that will massively increase the speed at which data is stored and transmitted. The method, reported in the February 2025 issue of Nature Photonics, was invented by three research students―Omer Kneller, Chen Mor, and Noa Yaffe―working in the lab of Prof. Nirit Dudovich in the Department of Physics of Complex Systems.
This new technology uses two laser beams. The first is a powerful one, made up of relatively long pulses, that modifies the optical delay experienced by light as it passes through a given material. The other laser, which emits extremely short attosecond pulses, functions as a slow-motion video camera of sorts. These attosecond pulses come in two copies which are ultimately brought together and―like the physical change that occurs when two sets of ripples meet on the surface of a body of water―interfere with one another. This interference allows the researchers to precisely reconstruct the change in the optical delay. Using this approach, the Dudovich team successfully measured how pulses of laser light changed the properties of single atoms. They were also able to characterize the interaction between light and complex materials.
Dr. Omer Kneller (left) and Chen Mor direct a laser beam before it enters the
experimental setup. The experiment required a powerful laser beam that
could produce exceptionally short, attosecond light pulses.
(Photo by Noa Yaffe from the Dudovich lab)
Prof. Dudovich believes this new method may eventually make it possible to create “snapshots” of electrons in motion, revealing phenomena that could generate important discoveries related to quantum mechanics―the theoretical framework that describes the behavior of matter and of light, and the interaction between them.
NIRIT DUDOVICH IS SUPPORTED BY:
* The Jay Smith and Laura Rapp Laboratory for Research in the Physics of Complex Systems
* The Jacques and Charlotte Wolf Research Fund in Support of Prof. Nirit Dudovich
* The André Deloro Institute for Space and Optics Research
* The Robin Chemers Neustein Professorial Chair