Transverse Brillouin spectrum

The longitudinal Brillouin spectrum appears when both the incident and scattered light are polarized vertically with respect to the scattering plane (/vv) The transverse Brillouin spectrum results when the incident polarization is perpendicular to the scattered polarization (Ihv =1vh). 

A Brillouin spectrum of commercial Mylar film is shown in Figure 8. The longitudinal (L) and transverse (T) Brillouin peaks are easily seen. 

Figure 8. Brillouin spectrum of commercial Mylar film showing longitudinal (L), transverse (T), and unknown ( ) Brillouin peaks...

The spectrum of amorphous bisphenol-A polycarbonate showing both longitudinal and transverse Brillouin peaks is shown in Figure 2. 

When Ts < < 10" sec, the transverse phonon velocity is imaginary and no transverse Brillouin peaks are observed. However, shear fluctuations do occur and they can couple with other modes of motion such as molecular reorientation. The spectrum that results is given by ... 

The Raman scattering of single-crystal graphite was found to contain a single narrow band (G-mode) at 1575 cm, that is assigned to the planar mode of the Brillouin zone center. However, jp -hybridized carbon, that is, single-crystal diamond, demonstrates a single first-order peak in the Raman spectrum, a narrow symmetric line at the frequency of 1332.5 cm (with a peak width of about 2.0 cm" ), which derives from the transverse TO phonon of symmetry. At... 

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