Coherent Anti-Stokes Raman Scattering (CARS) Correlation Spectroscopy

KEYWORDS:CARS ¥ correlation spectroscopy ¥ diffusion ¥ microscopy ¥nonlinearopticsCorrelationtechniqueshavebeenwidelyappliedformonitoringsignalfluctuationsinadefinedobservationvolume.Thecauseofthefluctuationscaneitherbechangesinthenumberdensityofparticlesintheprobevolumeorchangesintheirspectroscopicproperties.Ingeneral,theobservationvolumeischosentobeassmallaspossibleinordertomaximizetherelativeamplitudeofthefluctuations.Forthisreason,thelastyearshaveseenafruitfulexchange of newdevelopments in microscopyand correlationspectroscopy. Many different spectroscopic techniques, whichhavefirstbeenappliedtoreducetheobservationvolumeortoprovideanewcontrastmechanisminmicroscopyapplications,weresubsequentlyusedforcorrelationspectroscopy.Themostprominent of these developments is the use of confocalmicroscopyincombinationwithfluorescencecorrelationspec-troscopy(FCS).