Raman scattering in thin-film waveguides

It is shown that Raman spectra can be obtained from thin films by using the films as waveguides for the exciting laser light and efficiently collecting the scattered light. We have applied this technique to single-crystal GaN films epitaxially grown on c-plate Al2O3. The measured polarized Raman spectra enable all the Raman active modes to be determined for the GaN (point group C6v).