Raman Scattering | Principles, Applications, Spectroscopy

Raman Scattering

Introduction to Raman Scattering and Spectroscopy

Ring for tilbud

raman spectroscopy overview video

raman spectroscopy overview video
raman spectroscopy overview video
Raman Scattering process raman shift diagram

Stimulated Raman Scattering

stimulated raman scattering diagram

Surface Enhanced Raman Scattering

surface enhanced raman scattering diagram

Coherent Anti-Stokes Raman Scattering

coherent anti stokes raman scattering diagram
raman scattering diagram
raman spectroscopy instruments in chemical reactor
raman scattering spectroscopy

Citations and References


What causes Raman scattering?

Raman scattering occurs when photons of monochromatic light (laser) contact with a molecule, resulting in the emission of inelastic photons.

What is the difference between Rayleigh and Raman scattering?

When interacting with a molecule, most photons disperse elastically. A tiny percentage is inelastically dispersed at frequencies that differ from and are typically lower than the incoming photons. Rayleigh scatter refers to elastically scattered photons that have no analytical value whereas Raman scatter refers to photons that are inelastically scattered

What is Stimulated Raman Scattering (SRS)? 

Another type of non-linear Raman spectroscopy is stimulated Raman scattering. Stimulated Raman scattering occurs when there is an excess of Stokes photons in the excitation beam or when they are purposely introduced. This wavelength corresponds to the brightest mode in the standard Raman spectrum, which is then substantially amplified while all other Raman-active modes are muted. Read more on stimulated Raman scattering.

What is Surface Enhanced Raman Scattering (SERS)?

Surface enhanced Raman scattering is a method used to amplify weak Raman signals by use of nanostructured or roughened metal surfaces, typically of gold or silver. Read more on surface enhanced Raman scattering.

What is the Raman principle?

The Raman effect is founded on light scattering, which involves Rayleigh scattering (elastic) at the same wavelength as the incident beam, as well as Raman scattering (inelastic) at various wavelengths caused by molecular vibrations. Rayleigh scattering is about one million times more intense than Raman scattering.​ 

What is the history of Raman scattering?

In 1928, Sir C.V. Raman and K.S. Krishnan observed the phenomenon that is now known as the Raman Effect and is the basis for Raman spectroscopy.  The phenomenon involves the interaction of photons with a molecule followed by inelastic scattering typically at a lower energy. Generally, photons scatter elastically. These one-in-ten million lower energy, inelastic scattered photons are referred to as Stokes scattering and are specific to bonds within a molecule resulting in a unique spectral signature for a given molecular structure.  ​

Their experiment was done using monochromatic light, sunlight filtered to leave only a single color, and found in 1923 that a number of liquids did change the color of the light, but very weakly.  Then in 1927 they found a particularly strong color change from light scattered by glycerine where the incident blue light changed to green. Finally in 1928 the first Raman spectrum was constructed and subsequently has undergone numerous engineering improvements as material science has advanced in the areas of lasers, optics and detectors.