Editing Attosecond

{{short description|One quintillionth of a second}}
{{Use dmy dates|date=August 2021}}
{{Infobox unit
| name     = attosecond
| image    = 
| caption  = 
| symbol   = as
| standard = [[SI]]
| quantity = [[time]]
| units1   = [[SI units]]
| inunits1 = {{val|e=-18|ul=s}}
}}
An '''attosecond''' (abbreviated as '''as''') is a [[unit of time]] in the [[International System of Units]] (SI) equal to 10<sup>−18</sup> or <sup>1</sup>⁄<sub>1 000 000 000 000 000 000</sub> (one quintillionth) of a [[second]].<ref>{{Cite web |date=2019-04-07 |title=attosecond - Memidex dictionary/thesaurus |url=http://www.memidex.com/attosecond |access-date=2023-10-24 |archive-url=https://web.archive.org/web/20190407151606/http://www.memidex.com/attosecond |archive-date=7 April 2019 }}</ref> 

An attosecond is to a second, as a second is to approximately 31.69 billion years.<ref>{{Cite web |date=2007-11-11 |title=Exploring "Attosecond" Time - Steacie Institute for Molecular Sciences (SIMS) |url=http://steacie.nrc-cnrc.gc.ca/personal/corkum/atto5_e.html |access-date=2023-10-24 |archive-url=https://web.archive.org/web/20071111131259/http://steacie.nrc-cnrc.gc.ca/personal/corkum/atto5_e.html |archive-date=11 November 2007 }}</ref> 

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.

One attosecond is equal to 1000 [[Orders of magnitude (time)#Zeptosecond|zeptoseconds]], or 1/1000 [[Femtosecond|femtosecond]]. Because the next SI unit is 1000 times larger, measurements of 10<sup>−17</sup> and 10<sup>−16</sup> second are typically expressed as tens or hundreds of attoseconds.

== Common measurements ==

* 0.247 attoseconds: travel time of a [[photon]] across "the average bond length of molecular hydrogen"<ref>{{Cite journal |last1=Grundmann |first1=Sven |last2=Trabert |first2=Daniel |last3=Fehre |first3=Kilian |last4=Strenger |first4=Nico |last5=Pier |first5=Andreas |last6=Kaiser |first6=Leon |last7=Kircher |first7=Max |last8=Weller |first8=Miriam |last9=Eckart |first9=Sebastian |last10=Schmidt |first10=Lothar Ph. H. |last11=Trinter |first11=Florian |last12=Jahnke |first12=Till |last13=Schöffler |first13=Markus S. |last14=Dörner |first14=Reinhard |date=2020-10-16 |title=Zeptosecond birth time delay in molecular photoionization |url=https://www.sciencemag.org/lookup/doi/10.1126/science.abb9318 |journal=Science |language=en |volume=370 |issue=6514 |pages=339–341 |doi=10.1126/science.abb9318 |pmid=33060359 |arxiv=2010.08298 |bibcode=2020Sci...370..339G |s2cid=222412229 |issn=0036-8075}}</ref>
* 24.189... attoseconds: the [[Atomic units|atomic unit]] of time<ref>{{Cite web |title=CODATA Value: atomic unit of time |url=https://physics.nist.gov/cgi-bin/cuu/Value?aut |access-date=2023-10-24 |website=physics.nist.gov}}</ref>
* 43 attoseconds: the shortest pulses of laser light yet created<ref>{{Cite web |title=Optica Publishing Group |url=https://opg.optica.org/oe/viewmedia.cfm?uri=oe-25-22-27506&html=true |access-date=2023-10-24 |website=opg.optica.org}}</ref>
* 53 attoseconds: the shortest electron laser pulse ever created <ref>{{Cite journal |last1=Kim |first1=H. Y. |last2=Garg |first2=M. |last3=Mandal |first3=S. |last4=Seiffert |first4=L. |last5=Fennel |first5=T. |last6=Goulielmakis |first6=E. |date=January 2023 |title=Attosecond field emission |journal=Nature |language=en |volume=613 |issue=7945 |pages=662–666 |doi=10.1038/s41586-022-05577-1 |pmid=36697865 |issn=1476-4687|pmc=9876796 }}</ref><ref>{{Cite web |date=2023-02-17 |title=Attosecond electron pulses are claimed as shortest ever |url=https://physicsworld.com/a/attosecond-electron-pulses-are-claimed-as-shortest-ever/ |access-date=2023-02-17 |website=Physics World |language=en-GB}}</ref>
* 53 attoseconds: the second-shortest pulses of laser light created<ref>{{Cite journal |last1=Li |first1=Jie |last2=Ren |first2=Xiaoming |last3=Yin |first3=Yanchun |last4=Zhao |first4=Kun |last5=Chew |first5=Andrew |last6=Cheng |first6=Yan |last7=Cunningham |first7=Eric |last8=Wang |first8=Yang |last9=Hu |first9=Shuyuan |last10=Wu |first10=Yi |last11=Chini |first11=Michael |last12=Chang |first12=Zenghu |date=2017-08-04 |title=53-attosecond X-ray pulses reach the carbon K-edge |journal=Nature Communications |language=en |volume=8 |issue=1 |page=186 |doi=10.1038/s41467-017-00321-0 |pmid=28775272 |pmc=5543167 |bibcode=2017NatCo...8..186L |issn=2041-1723}}</ref><ref>{{Cite web |title=Watching quantum mechanics in action: Researchers create world record laser pulse |url=https://www.sciencedaily.com/releases/2012/09/120904150100.htm |access-date=2023-10-24 |website=ScienceDaily |language=en}}</ref>
* 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<ref>{{Citation |title=Beryllium-8 |date=2023-06-21 |url=https://en.wikipedia.org/w/index.php?title=Beryllium-8&oldid=1161298590 |work=Wikipedia |access-date=2023-10-24 |language=en}}</ref>
* 84 attoseconds: the approximate [[half-life]] of a [[Pion#Neutral pion decays|neutral pion]]
* 100 attoseconds: fastest-ever view of molecular motion<ref>{{Cite news |date=2006-03-04 |title=Fastest view of molecular motion |language=en-GB |url=http://news.bbc.co.uk/2/hi/science/nature/4766842.stm |access-date=2023-10-24}}</ref>
* 320 attoseconds: the estimated time it takes [[Electron|electrons]] to transfer between atoms<ref>{{Cite web |date=2016-05-11 |title=Electron timed hopping between atoms {{!}} New Scientist |url=https://www.newscientist.com/article/dn7700-electron-timed-hopping-between-atoms/ |access-date=2023-10-24 |archive-url=https://web.archive.org/web/20160511205529/https://www.newscientist.com/article/dn7700-electron-timed-hopping-between-atoms/ |archive-date=11 May 2016 }}</ref><ref>{{Cite journal |last1=Föhlisch |first1=A. |last2=Feulner |first2=P. |last3=Hennies |first3=F. |last4=Fink |first4=A. |last5=Menzel |first5=D. |last6=Sanchez-Portal |first6=D. |last7=Echenique |first7=P. M. |last8=Wurth |first8=W. |date=2005-07-01 |title=Direct observation of electron dynamics in the attosecond domain |url=https://ui.adsabs.harvard.edu/abs/2005Natur.436..373F |journal=Nature |volume=436 |issue=7049 |pages=373–376 |doi=10.1038/nature03833 |pmid=16034414 |bibcode=2005Natur.436..373F |s2cid=4411563 |issn=0028-0836}}</ref>

== 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-ejected into the neon nucleus.<ref>{{Cite web |title=Attosecond Physics becomes a Milestone |url=https://www.mpq.mpg.de/4857719/10_05_17 |access-date=2023-10-24 |website=www.mpq.mpg.de |language=en}}</ref>

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.<ref>{{Cite journal |url=https://iopscience.iop.org/article/10.1088/0031-8949/91/6/063011/meta |doi=10.1088/0031-8949/91/6/063011 |title=The birth of attosecond physics and its coming of age |date=2016 |last1=Krausz |first1=Ferenc |journal=Physica Scripta |volume=91 |issue=6 |bibcode=2016PhyS...91f3011K |s2cid=124590030 }}</ref>

== Applications ==

=== Need for more precise units ===
The [[Crystal structure|crystal lattice]] vibrates and molecules rotate on a scale of [[Picosecond|picoseconds]]. The creation and breaking of chemical bonds and molecular vibration happen in femtoseconds. Observing the motion of electrons happens on the attosecond scale.<ref>{{Cite web |title=The Nobel Prize in Chemistry 1999 |url=https://www.nobelprize.org/prizes/chemistry/1999/press-release/ |access-date=2023-10-24 |website=NobelPrize.org |language=en-US}}</ref>

The number of electrons in an atom and their [[Configuration management|configuration]] define an [[Elementary particle|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 state|quantum states]] of matter.<ref>{{Cite web |last=Canada |first=National Research Council |date=2017-06-15 |title=Importance of attosecond research |url=https://www.canada.ca/en/national-research-council/news/2017/06/importance_of_attosecondresearch.html |access-date=2023-11-04 |website=www.canada.ca}}</ref> 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.<ref>{{Cite web |title=The Nobel Prize in Physics 2023 |url=https://www.nobelprize.org/prizes/physics/2023/press-release/ |access-date=2023-11-05 |website=NobelPrize.org |language=en-US}}</ref>

=== Directly observing the wave oscillations of light ===
Using a method called [https://www.nature.com/articles/srep35594 attosecond streaking], people can see the electrical components of [[Electromagnetic radiation|EM waves]]. Scientists start with a gas of neon atoms and ionize them with a single ultrashort burst of [[Ultraviolet|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.<ref>{{Cite journal |last1=Goulielmakis |first1=E. |last2=Uiberacker |first2=M. |last3=Kienberger |first3=R. |last4=Baltuska |first4=A. |last5=Yakovlev |first5=V. |last6=Scrinzi |first6=A. |last7=Westerwalbesloh |first7=Th. |last8=Kleineberg |first8=U. |last9=Heinzmann |first9=U. |last10=Drescher |first10=M. |last11=Krausz |first11=F. |date=2004-08-27 |title=Direct Measurement of Light Waves |url=https://www.science.org/doi/10.1126/science.1100866 |journal=Science |language=en |volume=305 |issue=5688 |pages=1267–1269 |doi=10.1126/science.1100866 |pmid=15333834 |bibcode=2004Sci...305.1267G |s2cid=38772425 |issn=0036-8075}}</ref>

=== Short pulses of light ===
The 2023 [[Nobel Prize in Physics]] was [[List_of_Nobel_laureates_in_Physics#Laureates|awarded]] to [[Pierre Agostini]], [[Ferenc Krausz]], and [[Anne L'Huillier]] for demonstrating a way to create "almost unimaginably" short [[pulse]]s of light, measured in attoseconds. These pulses can be used to capture and study rapid processes inside [[atom]]s, such as the behavior of electrons.<ref name=bbcnobel>{{cite news |last=Gill |first=Victoria  |date=3 October 2023 |title=Nobel Prize for 'attosecond physicists' Agostini, L'Huillier and Krausz |url=https://www.bbc.com/news/science-environment-66964430 |work=[[BBC]]|access-date=8 May 2024}}</ref><ref name=nytnobel>{{cite news |last1=Bubola|first1=Emma|last2= Miller|first2= Katrina |date=3 October 2023 |title=Nobel Prize in Physics Awarded to 3 Scientists for Illuminating How Electrons Move|url=https://www.nytimes.com/2023/10/03/science/nobel-prize-physics.html|work=[[The New York Times]]|url-access=subscription|access-date=8 May 2024}}</ref>

==See also==
* [[SI unit]]
* [[Second]]
* [[femtosecond]]
* [[picosecond]]
* [[Nanosecond]]
* [[Microsecond]]
* [[Millisecond]]
* [[Jiffy (time)]]
* [[Orders of magnitude (time)]]

*[[Attosecond chronoscopy]]

==References==
{{Reflist|30em}}

{{Orders of magnitude seconds}}

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[[Category:Orders of magnitude (time)]]