Shulou(Shulou.com)11/24 Report--

CTOnews.com, October 3 (Xinhua)-- the 2023 Nobel Prize in Physics has been awarded to Pierre Agostini (Pierre Agostini), Ferenc Klaus (Ferenc Krausz) and Anne Luril (Anne L'Huillier) for their "experimental method of generating attosecond light pulses to study the dynamics of electrons in matter."

Officials said that "their contribution enabled people to study extremely short processes that were previously untraceable", while the prize of 11 million Swedish kronor (CTOnews.com) will be shared equally among the three winners.

The Royal Swedish Academy of Sciences said the three physicists "showed a way to make extremely short light pulses that can be used to measure the rapid process of electron movement or energy change". This "provides a new way for humans to explore the electronic world within atoms and molecules".

Since the time scale of observing the world is of the order of as (10-18 s), the spatial resolution that can be observed can also reach atomic scale (0.1s) and subatomic scale (such as the breaking and recombination of molecular bonds).

In such a time and space scale, the research boundaries of biology, chemistry and physics become increasingly blurred, because the root of these microscopic phenomena lies in the motion of electrons.

Therefore, attosecond light pulse arises at the historic moment. The emergence of attosecond pulsed laser is considered to be one of the most important milestones in the history of laser science, and its application prospect is inestimable. At present, it has become an important research means in physics, chemistry, biology and many other fields.

To put it simply, according to the duration of luminescence, we generally divide the laser into continuous laser and pulsed laser, in which the pulsed laser works by emitting light pulses at short intervals, and its peak power is very high.

With the continuous development of laser technology, the pulse width of laser is also shrinking. In 2001, Ferenc-Klaus research group successfully used gas high-order harmonics to generate a single optical pulse with a pulse width of 650 as, which made the optical pulse width reach the attosecond order of magnitude for the first time, and then its width continuously broke through. For example, Xi'an Optical Machinery Institute of China obtained 75 as attosecond optical pulse generation and measurement results in 2021.

At this point, you should have understood that attosecond light pulse is a kind of light pulse with very short luminous duration, whose pulse width is less than 1 fs (femtosecond, that is, 10-15 s).

It is worth mentioning that at present, attosecond pulse laser is mainly formed by high-order harmonics produced by femtosecond laser (also known as ultra-fast and ultra-intense laser) acting on inert gas.

The emergence of attosecond optical pulses enables people to combine attosecond ultra-high time resolution and atomic-scale ultra-high spatial resolution to realize the dream of controlling and understanding extremely ultrafast processes in the atomic-subatomic micro world.

In view of its huge potential application value, the United States, Europe and Japan regard attosecond laser technology as one of the most important development directions of laser science in the next 10 years.

Before the appearance of attosecond optical pulse, the theoretical basis of ultrashort pulse laser was Einstein's stimulated radiation of energy level transition. According to the theory of stimulated radiation, electrons at the bound energy level can only move around the nucleus and the energy stored is limited. Generally speaking, the corresponding wavelengths of photons emitted by the upper and lower two-level transitions are near the visible light, and the optical period of visible light is generally more than 1 fs, so it is obviously difficult to generate shorter attosecond pulses.

At present, attosecond optical pulses are often used to study ultrafast electron dynamics in atoms and molecules. The physical phenomena of atoms are mainly intraatomic electron ionization, multi-electron Auger decay, electron excitation relaxation and imaging, and so on. The research on molecules is mainly about the dissociation process and control of molecules, the coupling of molecular vibration and rotation with ultrafast electron motion, and so on.

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