Figure 4

Polarized Raman spectra of a monolayer graphene on a quartz plate. (a) Polarized Raman spectra of a monolayer graphene on a quartz plate in the forward-scattering geometry with differing angles (θ) of the laser incidence. Excitation laser wavelength was 532 nm. The black curves are Raman spectra measured with in-plane configuration and the red ones measured with out-of-plane configuration. (b, c) Normalized Raman intensity of the G-band (b) and the 2D-band (c) in out-of-plane configuration with respect to that in in-plane configuration as a function of laser incidence angle, respectively. The black lines represent cos² θ.