An attosecond (abbreviated as as) is a unit of time in the International System of Units (SI) equal to 10−18 or 11 000 000 000 000 000 000 (one quintillion) of a second.[1] An attosecond is to a second as a second is to about 31.71 billion years.[2] The attosecond is a tiny unit but it has various potential applications: it can observe oscillating molecules, the chemical bonds formed by atoms in chemical reactions, and other extremely tiny and extremely fast things.

Common measurements

  • 0.247 attoseconds: travel time of a photon across "the average bond length of molecular hydrogen"[3]
  • 24.189... attoseconds: the atomic unit of time[4]
  • 43 attoseconds: the shortest pulses of laser light yet created[5]
  • 53 attoseconds: the shortest electron laser pulse ever created [6][7]
  • 53 attoseconds: the second-shortest pulses of laser light created[8][9]
  • 82 attoseconds (approximately): half-life of beryllium-8, maximum time available for the triple-alpha process for the synthesis of carbon and heavier elements in stars[10]
  • 84 attoseconds: the approximate half-life of a neutral pion
  • 100 attoseconds: fastest-ever view of molecular motion[11]
  • 320 attoseconds: the estimated time it takes electrons to transfer between atoms[12][13]

Historical development


In 2001, Ferenc Krausz and his team at the Technical University of Vienna fired an ultrashort wavelength (7 femtoseconds) red laser pulse into a stream of neon atoms, where the stripped electrons were carried by the pulse and almost immediately re-eject into the neon nucleus.[14]

While capturing the attosecond pulse, the physicists also demonstrated its utility. They aimed attosecond and longer-wavelength red pulses at a type of krypton atom simultaneously: first, the electrons were knocked off; then, the red light pulse hit the electrons; finally, the energy was tested. Judging from the difference in the timing of these two pulses, the scientists obtained a very precise measurement of how long it took the electron to decay (how many attoseconds). Never before have scientists used such a short time scale to study the energy of electrons.[15]



Need for more precise units


The crystal lattice vibrates and molecules rotate on a scale of picoseconds. The creation and breaking of chemical bonds and molecular vibration happen in femtoseconds. Observing the motion of electrons happens on the attosecond scale.[16]

The number of electrons in an atom and their configuration define an element. Because attosecond pulses are faster than the motion of electrons in atoms and molecules, attosecond provides a new tool for controlling and measuring quantum states of matter.[17] These pulses have been used to explore the detailed physics of atoms and molecules and have potential applications in fields ranging from electronics to medicine.[18]

Directly observing the wave oscillations of light


Using a method called attosecond streaking, people can see the electrical components of EM waves. Scientists start with a gas of neon atoms and ionize them with a single ultrashort burst of UV radiation measured in attoseconds. The electric field of the infrared can then strongly influence the motion of the electrons. The electrons will be forced up and down as the field oscillates. Depending on when the electron is released, this process will emit different final energies. The final measurement of the electron's energy, as a function of the relative delay between the two pulses, clearly shows the traces of the electric field of the attosecond pulse.[19]

Short pulses of light


The 2023 Nobel Prize in Physics was awarded to Pierre Agostini, Ferenc Krausz, and Anne L'Huillier for demonstrating a way to create "almost unimaginably" short pulses of light, measured in attoseconds. These pulses can be used to capture and study rapid processes inside atoms, such as the behavior of electrons.[20][21]

See also



  1. ^ "attosecond - Memidex dictionary/thesaurus". 7 April 2019. Archived from the original on 7 April 2019. Retrieved 24 October 2023.
  2. ^ "Exploring "Attosecond" Time - Steacie Institute for Molecular Sciences (SIMS)". 11 November 2007. Archived from the original on 11 November 2007. Retrieved 24 October 2023.
  3. ^ Grundmann, Sven; Trabert, Daniel; Fehre, Kilian; Strenger, Nico; Pier, Andreas; Kaiser, Leon; Kircher, Max; Weller, Miriam; Eckart, Sebastian; Schmidt, Lothar Ph. H.; Trinter, Florian; Jahnke, Till; Schöffler, Markus S.; Dörner, Reinhard (16 October 2020). "Zeptosecond birth time delay in molecular photoionization". Science. 370 (6514): 339–341. arXiv:2010.08298. Bibcode:2020Sci...370..339G. doi:10.1126/science.abb9318. ISSN 0036-8075. PMID 33060359. S2CID 222412229.
  4. ^ "CODATA Value: atomic unit of time". Retrieved 24 October 2023.
  5. ^ "Optica Publishing Group". Retrieved 24 October 2023.
  6. ^ Kim, H. Y.; Garg, M.; Mandal, S.; Seiffert, L.; Fennel, T.; Goulielmakis, E. (January 2023). "Attosecond field emission". Nature. 613 (7945): 662–666. doi:10.1038/s41586-022-05577-1. ISSN 1476-4687. PMC 9876796. PMID 36697865.
  7. ^ "Attosecond electron pulses are claimed as shortest ever". Physics World. 17 February 2023. Retrieved 17 February 2023.
  8. ^ Li, Jie; Ren, Xiaoming; Yin, Yanchun; Zhao, Kun; Chew, Andrew; Cheng, Yan; Cunningham, Eric; Wang, Yang; Hu, Shuyuan; Wu, Yi; Chini, Michael; Chang, Zenghu (4 August 2017). "53-attosecond X-ray pulses reach the carbon K-edge". Nature Communications. 8 (1): 186. Bibcode:2017NatCo...8..186L. doi:10.1038/s41467-017-00321-0. ISSN 2041-1723. PMC 5543167. PMID 28775272.
  9. ^ "Watching quantum mechanics in action: Researchers create world record laser pulse". ScienceDaily. Retrieved 24 October 2023.
  10. ^ "Beryllium-8", Wikipedia, 21 June 2023, retrieved 24 October 2023
  11. ^ "Fastest view of molecular motion". 4 March 2006. Retrieved 24 October 2023.
  12. ^ "Electron timed hopping between atoms | New Scientist". 11 May 2016. Archived from the original on 11 May 2016. Retrieved 24 October 2023.
  13. ^ Föhlisch, A.; Feulner, P.; Hennies, F.; Fink, A.; Menzel, D.; Sanchez-Portal, D.; Echenique, P. M.; Wurth, W. (1 July 2005). "Direct observation of electron dynamics in the attosecond domain". Nature. 436 (7049): 373–376. Bibcode:2005Natur.436..373F. doi:10.1038/nature03833. ISSN 0028-0836. PMID 16034414. S2CID 4411563.
  14. ^ "Attosecond Physics becomes a Milestone". Retrieved 24 October 2023.
  15. ^ Krausz, Ferenc (2016). "The birth of attosecond physics and its coming of age". Physica Scripta. 91 (6). Bibcode:2016PhyS...91f3011K. doi:10.1088/0031-8949/91/6/063011. S2CID 124590030.
  16. ^ "The Nobel Prize in Chemistry 1999". Retrieved 24 October 2023.
  17. ^ Canada, National Research Council (15 June 2017). "Importance of attosecond research". Retrieved 4 November 2023.
  18. ^ "The Nobel Prize in Physics 2023". Retrieved 5 November 2023.
  19. ^ Goulielmakis, E.; Uiberacker, M.; Kienberger, R.; Baltuska, A.; Yakovlev, V.; Scrinzi, A.; Westerwalbesloh, Th.; Kleineberg, U.; Heinzmann, U.; Drescher, M.; Krausz, F. (27 August 2004). "Direct Measurement of Light Waves". Science. 305 (5688): 1267–1269. Bibcode:2004Sci...305.1267G. doi:10.1126/science.1100866. ISSN 0036-8075. PMID 15333834. S2CID 38772425.
  20. ^ Gill, Victoria (3 October 2023). "Nobel Prize for 'attosecond physicists' Agostini, L'Huillier and Krausz". BBC. Retrieved 8 May 2024.
  21. ^ Bubola, Emma; Miller, Katrina (3 October 2023). "Nobel Prize in Physics Awarded to 3 Scientists for Illuminating How Electrons Move". The New York Times. Retrieved 8 May 2024.