Spectroscopic characterization of ambers and amber-like materials

Longitudinal acoustic (LA) phonon of Baltic, Dominican and Kuji ambers, amber-like rosin and synthetic acrylic resin has been investigated by means of Brillouin light scattering (BLS) at room temperature. We observed a pair of LA phonon peaks and a broad quasi-elastic scattering peak in backscattering spectra from ambers. The LA phonon frequencies were found to be 16.97–17.11 GHz for Baltic ambers, 17.23–17.68 GHz for Dominican ambers and 17.70–17.97 GHz for Kuji ambers, respectively. We would like to point out that the LA phonon frequency can be a good physical quantity to specify the amber-producing district. We also present a correlation between the BLS spectrum and infrared absorption spectrum of ambers and amber-like materials.