Quantitative Coherent Raman Scattering Microscopy: New tools for the Material and Life Sciences

Abstract:

A series of advances over the past decade have made the combination of coherent Raman scattering (CRS) with optical microscopy a highly sensitive and chemically selective tool for the label-free and noninvasive analysis of chemical species or biological components inside a sub-femtoliter probe volume. By exploiting the coherent driving and detection of Raman modes in coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS), CRS microscopy allows the point-by-point chemical mapping of molecular compounds, which is often difficult to attain by conventional fluorescence and incoherent vibrational microscopy techniques. Here, we will focus on two CRS modalities that provide quantitative molecular information: (i) high-speed stimulated Raman loss (SRL) imaging at video-rates and (ii) hyperspectral CARS imaging that provides access to the full wealth of chemical and physical structure information of an a priori unknown molecular sample. We will discuss their underlying principles and demonstrate exemplifying applications for the 3D visualization of chemical composition as well as of molecular structure properties inside heterogeneous and complex materials, ranging from polymers to living cells.