Broadband Coherent Anti-Stokes Raman Scattering (BCARS) MicroSpectroscopy

The ability to noninvasively image the dynamic chemical composition within cells and tissues would revolutionize our understanding of biology and disease. Molecular vibrational imaging techniques detect the small oscillations between bonded atoms, providing dense spectral information about composition and state without the addition of fluorophores or dyes. Technologies, such as Raman and infrared microscopies, have offered this capability for over half a century, but significant limitations in speed, resolution, or sample preparation have prevented their ubiquity. Coherent Raman imaging (CRI) methods, proposed as the solution, have been practically confined to small increments of the vibrational spectrum with limited chemical specificity. Broadband coherent anti-Stokes Raman scattering (BCARS), a particular CRI modality, on the other hand, has demonstrated an unprecedented combination of speed, sensitivity, and spectral breadth, enabling full hyperspectral imagery in minutes rather than hours. Furthermore, as a coherent anti-Stokes Raman scattering (CARS)-based method, a coherent background is generated that is molecularly sensitive and can be used as a built-in internal reference at each pixel; thus, enabling directly comparable results between samples and spectra collected on different microscope systems.

In this seminar, I will present an introduction to BCARS microscopy from a theoretical and practical perspective. Specifically, covering the physics of signal generation and extraction of Raman signatures. Further, I will touch upon application space examples and our efforts towards quantitative imaging.