Coherent Anti-Stokes Raman Scattering (CARS)
Coherent anti-Stokes Raman Scattering (as well as Stimulated Raman Scattering) create high imaging contrast without labeling. The technology involves two laser beams. The pump laser beam and a Stokes laser beam interact, producing an anti-Stokes signal. CARS is sensitive to the vibrational modes of samples and visualizes the vibrational contrast of molecules. The samples, even living objects, remain almost unaffected.
A Coherent Anti-Stokes Raman Scattering (CARS) signal was first recorded in the mid-1960s. At that time, it was called “Three wave mixing experiment”. After ten years, first applications on biological samples were shown. CARS spectroscopy is used to get detailed information of molecules or identification of components within a sample, because of the structural fingerprint.
CARS – Microscopy is an imaging method which is based on the intrinsic vibrational contrast of certain molecules and thus allows a high-resolution representation of structures. Using two laser beams with a certain difference of the two frequencies, vibrational states of molecules can be probed. To differentiate between vibrational states, one of the beams, Pump or Stokes, must be tuneable. The resulting inelastic scattering of blue-shifted photons (Anti-Stokes or CARS – Signal) are used for imaging.
While fluorescence microscopy is more sensitive, CARS – Microscopy offers a higher resolution at lower power level due to the multi-photon process, without the need of complex preparation of the sample with dyes (label free) that can influence the sample and the results of the experiment. In respect to this, this method is suitable for studies on living samples (in vivo), whereby the sample remains virtually unaffected.
Datasheets & Brochures
APE picoEmerald CARS SRS rev.3.1 (pdf / english)
APE Reference Guide picoEmerald Okt 2017 Rev.3.2.1 (pdf / english)
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In our reference guide we present more than 50 + publications for which the picoEmerald has been used to employ Stimulated Raman Scattering or Coherent anti-Stokes Raman Spectroscopy. Here it is available for Download: APEs picoEmerald Reference List Edition October 2017