Hyper Rayleigh Scattering

Hyper Rayleigh Scattering (aka Harmonic Light Scattering or HRS) is one method for measuring the first hyperpolarizabilityβ. Another method is electric field induced second harmonic generation (EFISH)

Overview

Schematic of the HRS setup. CL = collimating lenses; LPF = long-pass filter; FL = 300-mm focusing lens; S = solution of chromophore in solvent of choice; DO = detection optics; IF = interference filter (950 nm)

In HRS A dilute sample of a test chromophore is prepared in a solvent. An incident laser generates a second harmonic signal, specifically the frequency double signal from excitation of the sample molecules. This can be related to the beta of the sample using this formula:

<math>\frac {I_{sample}} {I_{solvent}} = \frac {N_{sample} \langle \beta^2 _{sample} \rangle + N_{solvent} \langle \beta^2_{solvent}\rangle} {N_{solvent} \langle \beta^2_{solvent}\rangle}\,\!</math>

HRS spectrum for 1.5 μm TCP1 in CHCl₃

See Firestone 2004 .

There are a number of ways the HRS setup can use in non-linear optics research.

The dielectric properties of the solvent influence the β (solvatochromatism).

See Wikipedia on Rayleigh Scattering

See also Density Functional Theory

See Wikipedia on Raman Scattering

Technique

Video to come