What is the Raman effect?

In the first seven years after its discovery, the Raman Effect was the subject of more than 700 papers in the scientific literature, mostly by physicists who were using the technique to study the vibration and rotation of molecules and relating those phenomena to the molecular structure.

What is the effect of Raman scattering on Stokes photons?

The more Stokes photons that are already present, the faster more of them are added. Effectively, this amplifies the Stokes light in the presence of the pump light, which is exploited in Raman amplifiers and Raman lasers . Stimulated Raman scattering is a nonlinear optical effect.

What is the phase-shift of the Raman scattered beam?

Thus, a phase-shift Θ = 2πx(1/λ − 1/λ’) appears. For Θ = π, the scattered amplitudes are opposite, so that the Raman scattered beam remains weak. A crossing of the beams may limit the path x. Several tricks may be used to get a larger amplitude:

What is the best book on the Raman effect?

The Raman Effect 25 Smekal, A. (1923). Naturwissenschaften 11, 873. Sonnich Mortensen, O. and Massing, S. (1980). In: R. J. C. Clark and R. E. Hester (eds), Advances in Infrared Raman Spectroscopy. Heyden, London, vol. 6. Stoicheff, B. (1963).

The Raman effect is named after Indian scientist C. V. Raman, who discovered it in 1928 with assistance from his student K. S. Krishnan. Raman was awarded the 1930 Nobel Prize in Physics for his discovery of Raman scattering. The effect had been predicted theoretically by Adolf Smekal in 1923.

How to increase the amplitude of a Raman scattered beam?

For Θ = π, the scattered amplitudes are opposite, so that the Raman scattered beam remains weak. A crossing of the beams may limit the path x. Several tricks may be used to get a larger amplitude: In an optically anisotropic crystal, a light ray may have two modes of propagation with different polarizations and different indices of refraction.

What is a normal mode in Raman?

In general, a normal mode is Raman active if it transforms with the same symmetry of the quadratic forms , which can be verified from the character table of the molecule’s point group. As with IR spectroscopy, only fundamental excitations (

What is Raman resonance in optically anisotropic crystal?

In an optically anisotropic crystal, a light ray may have two modes of propagation with different polarizations and different indices of refraction. If energy may be transferred between these modes by a quadrupolar (Raman) resonance, phases remain coherent along the whole path, transfer of energy may be large.