Superresolution vibrational imaging by simultaneous detection of Raman and hyper-Raman scattering

Abstract

We have developed a superresolution vibrational imaging method by simultaneous detection of Raman and hyper-Raman scattering. Raman and hyper-Raman images obtained with the same laser spot carry independent information on the sample spatial distribution, owing to different signal dependence (linear in Raman and quadratic in hyper-Raman) on the incident light intensity. This information can be quantitatively analyzed to recover the incident light intensity distribution at the focal plane. A superresolution vibrational image is then derived by the constrained deconvolution of the images by the obtained incident light intensity distribution. This method has been applied to a TiO(2) nanostructure and the obtained superresolution image was compared with a scanning electron microscopy image. The spatial resolution achieved by the present method is evaluated to be 160 nm, which is more than twice better than the diffraction limited resolution. (C) 2011 Optical Society of America