Parth G's video: Nobel Prize in Physics 2023 Explained: The Fastest Light Pulses Ever Made

The 2023 Nobel Prize in Physics has been awarded to three experimental physicists at the cutting-edge of the subject! Pierre Agostini, Ferenc Krausz, and Anne L'Huillier were each given a 1/3 share of the prize, and it's exciting to see that fairly new, experimental physics is being recognised on such a large scale. The award was given for work on "attosecond physics", a fairly new area of physics studying things that happen very quickly (on the attosecond, or 10*(-18) second level). The Nobel Prize awardees have worked on generating pulses of (laser) light that are on the order of attoseconds in length. This is impossible to do by simply switching on and off our laser, since doing so this quickly is mechanically impossible. Instead, scientists use the principle of superposition to generate resultant light waves that are formed of very short pulses of high amplitude. To do so, they need to combine multiple light waves that are different from each other by a constant frequency difference. For example, light pulses can be combined by adding together waves that are 990 Hz, 1000 Hz, and 1010 Hz. These waves, which are separated from the next by a constant (10 Hz in this case) will combine together and interfere to generate regular pulses. But this will only happen if the phases and amplitudes of each combined wave are correct. Not long after the invention of the laser, scientists managed to generate pulses on the order of microseconds in length. This quickly dropped to nanoseconds, then femtoseconds. But as time has passed, the femtosecond barrier has been difficult to break due to limits on both physical systems and our understanding of physics. Our Nobel Prize winners have all worked on generating attosecond pulses of light, which finally broke the femtosecond barrier. One method is High Harmonic Generation (HHG), where a pulsed laser fired into a gas creates higher order harmonics that are equally spaced in frequency. Our winners showed that these harmonics could be forced to have the right phases and amplitudes such that, when combined, they created pulses on the order of attoseconds. But what are these pulses even used for? One use is outlined in the Nobel Committee's description of why these scientists won the prize. They state that the pulses can be used to understand electron dynamics in matter. One example of this that we see in the video is when an inner-shell electron is ejected from an atom. It leaves behind a hole, which can be filled by another electron from a higher shell. But this happens so fast that even femtosecond pulses are too fast to give us an exact picture of what's going on. We don't know if a single electron falls from a higher level to the lower one, or if all the electrons rearrange, or if something else entirely happens. We need attosecond pulses to give us more information about how electrons behave within atoms and molecules. Thanks for watching, please do check out my links: MERCH - https://parth-gs-merch-stand.creator-spring.com/ INSTAGRAM - @parthvlogs PATREON - patreon.com/parthg MUSIC CHANNEL - Parth G Music Here are some affiliate links for things I use! Quantum Physics Book I Enjoy: https://amzn.to/3sxLlgL My Camera: https://amzn.to/2SjZzWq ND Filter: https://amzn.to/3qoGwHk Timestamps: 0:00 - Pulsed Lasers and Interference 1:38 - How to Make Pulses (and Make Them Shorter) 2:54 - The History of Pulsed Light 3:55 - A Breakthrough! High Harmonic Generation 4:29 - Applications: Electron Dynamics in Matter 5:35 - Conclusion