Attosecond made its mark on the Nobel Prize in Physics: So, what does this mean?



What is an attosecond measurement?

An attosecond is an extremely brief unit of time, equivalent to the number of seconds since the universe began 13.8 billion years ago(shown in the figure above). To illustrate, it takes ten billion attoseconds for a flash of light to traverse a room. Essentially, attoseconds are used to measure ultrafast processes.

Why do we need to measure that fast?

Measuring on an attosecond scale is essential to capture lightning-fast electron movements, unraveling fundamental aspects of matter. This knowledge not only advances our understanding of physics but also holds the key to groundbreaking applications in electronics and medicine.

Exploring Electron Dynamics: The Significance of Shorter Pulses and High Overtones in Attosecond Measurements

In the pursuit of attosecond measurements, scientists harness the power of shorter light pulses through a fascinating phenomenon: high overtones. By exploring the mathematical intricacies of waveforms, researchers demonstrate that combining multiple wavelengths in laser light generates shorter pulses. This innovative approach, utilizing overtones induced when laser light passes through a gas, allows for the creation of ultrashort pulses essential for capturing the swift dance of electrons within atoms. This breakthrough not only expands the temporal boundaries of scientific observation but also sets the stage for groundbreaking experiments in attosecond physics.

Why does Escaping electrons create overtones?

When laser light interacts with gas atoms, it prompts electrons to break free from their atomic confines. As these liberated electrons return to their nuclei, they release excess energy in the form of light pulses, known as overtones. This phenomenon offers a key insight into the intricate world of electron dynamics, enabling scientists to study and measure ultrafast processes on an attosecond scale.

Laser light interacts with atoms in a gas

In a pivotal phase of the experiment, laser light engages in a complex interplay with atoms within a gaseous environment, laying the foundation for a series of captivating events as visually depicted in the accompanying photo. At the outset, we encounter an electron bound to an atom's nucleus, typically lacking the requisite energy to free itself from the potent grip of the atom's electrical field. This constrained state, confined within the atom's energy well, underscores the initial challenge faced by the electron.


  1. Energy Barrier: Initially, an electron bound to an atom's nucleus lacks the energy needed to escape the atom's electrical field, effectively confined within its energy well.
  2. Laser-induced Distortion: The laser pulse distorts the atom's field, allowing quantum mechanics to come into play. The electron, tethered by a narrow barrier, exploits quantum tunneling to escape.
  3. Energy Boost: Once free, the electron interacts with the laser field, gaining additional energy. As the field changes direction, the electron is tugged back along its path.
  4. Ultraviolet Flash: To reattach to the atom's nucleus, the electron sheds its excess energy in the form of an ultraviolet flash. The wavelength of this flash is intricately linked to the laser field, offering insights into the electron's journey. This captivating process forms the basis for overtones, attosecond pulses, and a deeper understanding of electron dynamics within atoms.