请输入您要查询的百科知识：

　

词条 Laser-induced fluorescence
释义

  1. Types

  2. Applications

  3. See also

  4. Notes

{{more footnotes|date=December 2010}}Laser-induced fluorescence (LIF) or laser-stimulated fluorescence (LSF)[1] is a spectroscopic method in which an atom or molecule is excited to a higher energy level by the absorption of laser light followed by spontaneous emission of light.[2][3] It was first reported by Zare and coworkers in 1968.[4][5]

LIF is used for studying structure of molecules, detection of selective species and flow visualization and measurements. The wavelength is often selected to be the one at which the species has its largest cross section. The excited species will after some time, usually in the order of few nanoseconds to microseconds, de-excite and emit light at a wavelength longer than the excitation wavelength. This fluorescent light is typically recorded with a photomultiplier tube (PMT) or filtered photodiodes.

Types

Two different kinds of spectra exist, disperse spectra and excitation spectra.

The disperse spectra are performed with a fixed lasing wavelength, as above and the fluorescence spectrum is analyzed. Excitation scans on the other hand collect fluorescent light at a fixed emission wavelength or range of wavelengths. Instead the lasing wavelength is changed.

An advantage over absorption spectroscopy is that it is possible to get two- and three-dimensional images since fluorescence takes place in all directions (i.e. the fluorescence signal is usually isotropic). The signal-to-noise ratio of the fluorescence signal is very high, providing a good sensitivity to the process. It is also possible to distinguish between more species, since the lasing wavelength can be tuned to a particular excitation of a given species which is not shared by other species.

LIF is useful in the study of the electronic structure of molecules and their interactions. It has also been successfully applied for quantitative measurement of concentrations in fields like combustion, plasma, spray and flow phenomena (such as molecular tagging velocimetry), in some cases visualizing concentrations down to nanomolar levels. LED-induced fluorescence has been used in situ to delineate aromatic hydrocarbon contamination as a cone penetrometer add on module and also as a percussive capable asset.

Applications

  • Detection of purity[6]
  • Optical tumor diagnosis{{citation needed|date=April 2016}}
  • Imaging of paleontological specimens[1]
  • Detection and quantification of biomolecules and biological processes (e.g DNA sequencing, trace protein analysis, polymerase chain reaction products, and single-cell analysis)[7][8]

See also

  • Fluorescence microscope
  • Planar laser-induced fluorescence
  • Ultrafast laser spectroscopy

Notes

{{Commons category}}
1. ^1 {{cite journal|last1 = Kaye | first1 = T.G. | last2 = Falk | first2 = A.R. | last3 = Pittman | first3 = M. | last4 = Sereno | first4 = P.C. | last5 = Martin | first5 = L.D. | last6 = Burnham | first6 = D.A. | first7 = E. | last7 = Gong | first8 = X. | last8 = Xu | first9 = Y. | last9 = Wang | date = 2015 | title = Laser-Stimulated Fluorescence in Paleontology | journal = PLoS ONE | volume = 10 | issue = 5 | page = e0125923 | doi = 10.1371/journal.pone.0125923 | url = http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0125923}}
2. ^{{cite journal|last1=Kinsey|first1=J L|title=Laser-Induced Fluorescence|journal=Annual Review of Physical Chemistry|volume=28|issue=1|year=1977|pages=349–372|issn=0066-426X|doi=10.1146/annurev.pc.28.100177.002025|bibcode = 1977ARPC...28..349K }}
3. ^{{cite book|author1=Richard W. Solarz|author2=Jeffrey A. Paisner|title=Laser Spectroscopy and its Applications|url=https://books.google.com/books?id=QdG2DZLQBLQC&pg=PA623|date=29 September 1986|publisher=CRC Press|isbn=978-0-8247-7525-4|pages=623–}}
4. ^{{cite journal|last1=Tango|first1=William J.|title=Spectroscopy of K2 Using Laser-Induced Fluorescence|journal=The Journal of Chemical Physics|volume=49|issue=10|year=1968|pages=4264|issn=0021-9606|doi=10.1063/1.1669869|bibcode = 1968JChPh..49.4264T }}
5. ^{{Cite journal | last1 = Zare | first1 = R. N. | doi = 10.1146/annurev-anchem-062011-143148 | title = My Life with LIF: A Personal Account of Developing Laser-Induced Fluorescence | journal = Annual Review of Analytical Chemistry | volume = 5 | pages = 1–14 | year = 2012 | pmid = 22149473| pmc = |bibcode = 2012ARAC....5....1Z }}
6. ^{{cite web | last = Takeyuki | first = Tanaka | display-authors = etal | authorlink = | coauthors = | title = The Application of Laser Induced Fluorescence Spectroscopy to Measurement of Purity Level in Textiles | work = | publisher = Jido Seigyo Rengo Koenkai | date = | url = http://sciencelinks.jp/j-east/article/200605/000020060506A0129627.php | format = | doi = | accessdate = 11 October 2008 | deadurl = yes | archiveurl = https://web.archive.org/web/20110213024518/http://sciencelinks.jp/j-east/article/200605/000020060506A0129627.php | archivedate = 13 February 2011 | df = }}
7. ^{{Cite journal|last=Lin|first=Yang-Wei|last2=Chiu|first2=Tai-Chia|last3=Chang|first3=Huan-Tsung|date=2003|title=Laser-induced fluorescence technique for DNA and proteins separated by capillary electrophoresis|url=https://dx.doi.org/10.1016/S1570-0232(03)00363-5|journal=Journal of Chromatography B|volume=793|issue=1|pages=37–48|doi=10.1016/s1570-0232(03)00363-5|issn=1570-0232|via=}}
8. ^{{Cite journal|last=Zare|first=Richard N.|date=2012-07-19|title=My Life with LIF: A Personal Account of Developing Laser-Induced Fluorescence|url=https://doi.org/10.1146/annurev-anchem-062011-143148|journal=Annual Review of Analytical Chemistry|language=en|volume=5|issue=1|pages=1–14|doi=10.1146/annurev-anchem-062011-143148|issn=1936-1327|bibcode=2012ARAC....5....1Z}}

2 : Spectroscopy|Fluorescence
随便看

　

开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。

　

Copyright © 2023 OENC.NET All Rights Reserved
京ICP备2021023879号 更新时间：2024/11/12 16:01:37