Apparent Raman spectral shifts from nano-structured surfaces

作者：Tishkova V^*; Bacsa W S

来源：Applied Physics Letters, 2012, 100(17): 173105.

DOI：10.1063/1.4704928

We observe Raman spectral shifts when scanning the focal spot over trenches in gallium arsenide. The Raman spectral shifts induced by topography are only present when the trenches are parallel to the spectrometer grating grooves. The topography induced spectral shifts are explained by spatial modification of the emitted beam due to surface topography leading to a non uniform illumination of the focal spot. The non uniform illumination of the focal spot influences the grating angle leading to the observed spectral shift. Apparent Raman spectral shifts of nano-structured surfaces can be reduced when under focusing at the expense of recording lower signals or using objectives with a low numerical aperture. This shows that topography induced spectral shifts need to be taken into account when recording optical spectra from nano-structured surfaces.

• 出版日期2012-4-23