Physics and Applications of Dual-Comb Coherent Anti-Stokes Raman Spectroscopy for Biomedical Imaging

With the rapid advancement of biology and life sciences, there is an increasing demand for observing sub-cellular structures and molecular interactions at submicroscopic or even single-molecule levels, providing critical insights into life activities and disease diagnostics. Raman spectroscopy, which relies on molecular vibrational energy transitions, enables non-label and non-invasive cellular visualization, holding significant potential for modern medical technology. The microscopy method based on the coherent anti-Stokes Raman scattering effect, a novel visualization modality with superior signal intensity, chemical specificity, and label-free capability, demonstrates great promise in biomedical applications. Recently, dual-comb technology, consisting of two frequency combs with slightly different repetition rates, as a powerful light source has been successfully applied in CARS applications with the excellent performance characteristics of rapid acquisition, high resolution, and high signal-to-noise ratio. The dual-comb technique allows to clearly resolve sharp molecular lines and could suppress the non-resonant background in CARS. Through recent research progress, this work reviews the generation of dual-comb lasers based on a single cavity, the development of dual-comb CARS systems, and their biomedical applications. This review could provide further insights into high-resolution dual-comb CARS and potential ways to design such technology for potential biomedical applications.