High-throughput Raman and surface-enhanced Raman microscopy

Abstract

Line-scan Raman microscopy (LSRM) is a versatile technique for high throughput label-free chemical mapping. The LSRM instrument achieves a hundred-fold throughput advantage over conventional point-scan Raman microscopy, by projecting a laser line onto the sample and image the Raman scattered light from the entire line using a grating spectrograph and a CCD camera. Two-dimensional chemical maps can be generated by scanning the projected line in the transverse direction. Areas of 100 x 100 μm 2 can be rapidly mapped with sub-micron spatial resolution and 100% fill factor. The instrument enables rapid classification of microparticles with similar shape, size and refractive index based on their chemical composition. We have achieved an equivalent imaging throughput of 100 microparticles/sec for 1 μm polystyrene beads. We have extended the technology to surface-enhanced Raman imaging, by characterizing the spatial uniformity of the SERS response of several types of nanostructured plasmonic substrates.