Diffusing-wave spectroscopy: Difference between revisions

Revision as of 11:59, 9 May 2016

Latest revision as of 13:04, 15 April 2025

(13 intermediate revisions by 9 users not shown)

Line 1:

'''Diffusing-wave spectroscopy''' ('''DWS''') is an opticaoptical technique derived from [[dynamic light scattering]] (DLS) that studies the dynamics of scattered light in the limit of strong multiple scattering.<ref>

{{cite journal

|authorauthor1=G. Maret, |author2=P. E. Wolf |year=1987

|year=1987

|title=Multiple light scattering from disordered media. The effect of brownian motion of scatterers

|journal=[[Zeitschrift für Physik B]]

Line 8 ⟶ 7:

|doi=10.1007/BF01303762

|bibcode = 1987ZPhyB..65..409M

|issue=4 |s2cid=121962976 }}</ref><ref>

{{cite journal

|authorauthor1=D. J. Pine, |author2=D. A. Weitz, |author3=P. M. Chaikin, and |author4=E. Herbolzheimer |year=1988

|year=1988

|title=Diffusing wave spectroscopy

|journal=[[Physical Review Letters]]

|volume=60 |pages=11341134–1137

|doi=10.1103/PhysRevLett.60.1134

|bibcode=1988PhRvL..60.1134P

|issue=12

|pmid=10037950 }}</ref> It has been widely used in the past to study colloidal [[Suspension (chemistry)|suspension]]s, [[emulsions]], [[foams]], gels, biological media and other forms of [[soft matter]]. If carefully calibrated, DWS allows the quantitative measurement of microscopic motion in a soft material, from which the [[rheological]] properties of the complex medium can be extracted ''via'' the so-called [[microrheology]] approach.

==One-speckle diffusing-wave spectroscopy==

Line 30 ⟶ 28:

<math>g_2(\tau)=\frac{\langle I(t)I(t+\tau)\rangle_t}{\langle I(t)\rangle_t^2}</math>

For the case of non-interacting particles suspended in a (complex) fluid a direct relation between g₂-1 and the [[mean squared displacement]] of the particles <Δr²> can be established. Let's us note P(s) the probability density function (PDF) of the photon path length s. The relation can be written as follows:<ref>

{{cite journal

|author=[[Frank Scheffold|F. Scheffold]]

|author-link=Frank Scheffold

|year=2004

|year=19872004

|title=New trends in optical microrheology of complex fluids and gels

|url=http://w3.lcvn.univ-montp2.fr/~lucacip/NewTrendsMicroRheology.pdf

|journal=[[Progress in Colloid and Polymer Science]]

|volume=123 |pages=141–146

|volume=123

|doi=10.1007/b11748

|volume=123 |pages=141–146

|isbn=978-3-540-00553-7

|doi=10.1007/b11748

|display-authors=etal}}</ref>

|isbn=978-3-540-00553-7

|display-authors=etal}}</ref>

|url-status=dead

|archiveurl=https://web.archive.org/web/20110721023401/http://w3.lcvn.univ-montp2.fr/~lucacip/NewTrendsMicroRheology.pdf

|archivedate=2011-07-21

}}</ref>

<math>g_2(\tau)-1=[\int {ds P(s) \exp(-(s/l*)k_0^2 \langle\Delta r^2(\tau)\rangle) }]^2</math>

Line 52 ⟶ 56:

For less thick cells and in transmission, the relationship depends also on l* (the transport length).<ref>

{{cite book

|authorauthor1=D. A. Weitz, |author2=D. J. Pine |year=1993

|year=1993

|chapter=Diffusing-wave spectroscopy

|editor=W. Brown

Line 62 ⟶ 65:

}}</ref>

For quasi-transparent cells, an angle-independent variant method called cavity amplified scattering spectroscopy<ref>{{Cite journal |last1=Graciani |first1=Guillaume |last2=King |first2=John T. |last3=Amblard |first3=François |date=2022-08-30 |title=Cavity-Amplified Scattering Spectroscopy Reveals the Dynamics of Proteins and Nanoparticles in Quasi-transparent and Miniature Samples |url=https://pubs.acs.org/doi/10.1021/acsnano.2c06471 |journal=ACS Nano |volume=16 |issue=10 |language=en |pages=16796–16805 |doi=10.1021/acsnano.2c06471 |pmid=36039927 |arxiv=2111.09616 |s2cid=244345602 |issn=1936-0851}}</ref> makes use of an [[integrating sphere]] to isotropically probe samples from all directions, elongating photon paths through the sample in the process, allowing for the study of low turbidity samples under the DWS formalism.

==Multispeckle Diffusing-Wave Spectroscopy (MSDWS)==

==Multispeckle Diffusingdiffusing-Wavewave Spectroscopyspectroscopy (MSDWS)==

This technique either uses a camera to detect many speckle grains (see [[speckle pattern]]) or a ground glass to create a large number of speckle realizations (Echo-DWS <ref>{{Cite web|url=http://spie.org/x8591.xml?highlight=x2404&ArticleID=x8591|title=Light scattering technique reveals properties of soft solids}}</ref>). In both cases an average over a large number of statistically independent intensity values is obtained, allowing a much faster data acquisition time.

<gallery>

Line 71 ⟶ 76:

<math>g_2(\tau)=\frac{\langle I(t)I(t+\tau)\rangle_p}{\langle I(t)\rangle_p^2}</math>

MSDWS is particularly adapted for the study of slow dynamics and non ergodic media. Echo-DWS allows seamless integration of MSDWS in a traditional DWS-scheme with superior [[temporal resolution]] down to 12&nbsp;ns.<ref>

{{cite journal

|authorauthor1=P. Zakharov, |author2=F. Cardinaux, and |author3=F. Scheffold |year=2006

|year=2006

|title=Multispeckle diffusing-wave spectroscopy with a single-mode detection scheme

|journal=[[Physical Review E]]

|volume=73 |issue=1 |pages=011413

|doi=10.1103/PhysRevE.73.011413

|pmid=16486146 |arxiv = cond-mat/0509637 |bibcode = 2006PhRvE..73a1413Z |s2cid=6251182 }}</ref> Camera based adaptive image processing allows online measurement of particle dynamics for example during drying.<ref>

{{cite journal

|author1=L. Brunel |author2=A. Brun |author3=P. Snabre |author4=L. Cipelletti |title=Adaptive Speckle Imaging Interferometry: a new technique for the analysis of microstructure dynamics, drying processes and coating formation

|author=L. Brunel, A. Brun, P. Snabre, and L. Cipelletti

|title=Adaptive Speckle Imaging Interferometry: a new technique for the analysis of microstructure dynamics, drying processes and coating formation

|url=http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-15-23-15250

|journal=[[Optics Express]]

Line 89 ⟶ 92:

|doi=10.1364/OE.15.015250

|bibcode = 2007OExpr..1515250B

|pmid=19550809|arxiv = 0711.1219 |s2cid=5753232 }}</ref>

==References==

{{reflistReflist}}

==External links==

*[https://web.archive.org/web/20110930154856/http://www.formulaction.com/technology_dws.html/ Diffusing Wave Spectroscopy Overview with video]

*[http://www.lsinstruments.ch/technology/diffusing_wave_spectroscopy_dws/ Diffusing Wave Spectroscopy Overview with Animations] {{Webarchive|url=https://web.archive.org/web/20140520215951/http://www.lsinstruments.ch/technology/diffusing_wave_spectroscopy_dws |date=2014-05-20 }}

*[http://www.lsinstruments.ch/technology/diffusing_wave_spectroscopy_dws/dws_particle_sizing/ Particle Sizing using Diffusing Wave Spectroscopy] {{Webarchive|url=https://web.archive.org/web/20140520220247/http://www.lsinstruments.ch/technology/diffusing_wave_spectroscopy_dws/dws_particle_sizing/ |date=2014-05-20 }}

[[Category:Spectroscopy]]