Wide-Field Super-Resolved Raman Imaging of Carbon Materials

In recent decades, Raman spectroscopy techniques have played an important role in the research of biology, chemistry, and materials. As a label-free chemical contrast imaging method, the resolving capacity of conventional far-field spontaneous Raman imaging is limited by the diffraction to half of the wavelength. On the other hand, the time-consuming mechanical scanning process often takes minutes to hours for large-scale imaging. Here, we report a high-throughput super-resolution Raman imaging method termed structured illumination Raman microscopy (SIRM). The achievable spatial resolution of this technique was up to 80 nm, and the spectral resolution was up to 50 cm–1. For demonstration, we used this technique to characterize several typical carbon materials, such as carbon nanotubes and graphene flakes. The samples were imaged in a field of view of 32 μm × 32 μm with megapixel sampling, and the imaging time of a specific Raman band was reduced to seconds. This technique shows potential in the fast large-scale characterization of nanomaterials in situ, which may contribute to the quality evaluation in the fabrication of carbon-based devices.