What is an attosecond? A physical chemist explains the tiny time scale behind Nobel Prize-winning research

[Admin]

A group of three researchers earned the 2023 Nobel Prize in physics for work that has revolutionized how scientists study the electron – by illuminating molecules with attosecond-long flashes of light.

What is an attosecond? A physical chemist explains the tiny time scale behind Nobel Prize-winning research : Read more

 

[OmShankar]

This article just rephrases more of the same information. How is an Attosecond pulse created? How is it used? None of that. Even after this article, we are just to take for granted that this is possible, without any explanation. Great.

 

[Danny1961#]

Ok...So to create an attosecond pulse, The process is meticulous and requires precise control of laser pulses. First, an intense femtosecond laser pulse is generated, which typically falls within the visible or near-infrared spectrum.

1. High Harmonic Generation (HHG): The process primarily used for creating attosecond pulses is High Harmonic Generation (HHG). In this method, the intense femtosecond laser pulse is focused onto a noble gas target, usually argon or helium.
2. Nonlinear Interaction: As the laser pulse interacts with the gas atoms, it causes a nonlinear response. The high intensity of the laser field leads to the generation of odd harmonics in the extreme ultraviolet (XUV) and soft X-ray regions.
3. Attosecond Pulse Formation: Due to the short duration of the driving laser pulse, the harmonic generation process produces bursts of XUV or soft X-ray radiation that are incredibly short, typically in the attosecond range (1 attosecond = 10^-18 seconds).
4. Isolation and Characterization: Sophisticated techniques are then employed to isolate and characterize these attosecond pulses. Techniques like attosecond streaking or attosecond transient absorption spectroscopy are used to study their properties.

They have several applications sir,

• Studying Electron Dynamics: Attosecond pulses allow physicists to probe and control electron motion in atoms and molecules. This is crucial for understanding fundamental processes in chemistry and physics.
• Attosecond Pump-Probe Experiments: Researchers use attosecond pulses to perform pump-probe experiments, where one attosecond pulse (the pump) excites a sample, and another attosecond pulse (the probe) measures its response. This enables the study of ultrafast processes, such as electron migration and charge transfer.
• Imaging Electronic Structure: Attosecond pulses can be used in imaging techniques like attosecond photoelectron spectroscopy to map the electronic structure of atoms and molecules.
• Real-Time Observations: Attosecond pulses enable real-time observation of electronic motion, making it possible to investigate phenomena like electron tunneling and ionization with unprecedented temporal resolution.