Coherent Raman scattering microscopy: capable solution in search of a larger audience

Abstract

Significance: Coherent Raman scattering (CRS) microscopy is an optical imaging technique with capabilities that could benefit a broad range of biomedical research studies.Aim: We reflect on the birth, rapid rise, and inescapable growing pains of the technique and look back on nearly four decades of developments to examine where the CRS imaging approach might be headed in the next decade to come.Approach: We provide a brief historical account of CRS microscopy, followed by a discussion of the challenges to disseminate the technique to a larger audience. We then highlight recent progress in expanding the capabilities of the CRS microscope and assess its current appeal as a practical imaging tool.Results: New developments in Raman tagging have improved the specificity and sensitivity of the CRS technique. In addition, technical advances have led to CRS microscopes that can capture hyperspectral data cubes at practical acquisition times. These improvements have broadened the application space of the technique. Conclusion:The technical performance of the CRS microscope has improved dramatically since its inception, but these advances have not yet translated into a substantial user base beyond a strong core of enthusiasts. Nonetheless, new developments are poised to move the unique capabilities of the technique into the hands of more users.

Background signals in stimulated Raman scattering microscopy and current solutions to avoid them

“…In fact, many of the proposed schemes require rather complex technical solutions, have optimal performances only in limited regions of the Raman spectrum, or necessitate manual adjustments and optimizations hindering their automation, a critical requirement for usability by non-specialists. Indeed, the development of an easy-to-use and turn-key operation machine is necessary for SRS microscopy to reach a bigger community [91].…”

“…The SRGAL scheme allows background signal suppression and gives an improved SNR compared to conventional IM-SRS, allowing to perform measurements two times faster [88]. As pointed out by Fimpel et al [89], an additional feature of the SRGAL scheme is the suppression of the background affecting the SREF signal [90,91] by performing the fluorescence detection at the beat frequency f S þ f P by means of a third LIA.…”

Vibrational imaging of metabolites for improved microbial cell strains

“…Some Raman-active chemical markers that have become mainstays for SRS imaging include the band associated with the C=C–H stretching modes in unsaturated fatty acids and the modes around 2845 and , respectively. 41 – 43 …”

Raman Scattering-Based Biosensing: New Prospects and Opportunities

“…Under these conditions, the generation of various optical harmonics arises, including coherent anti-Stokes and stimulated Raman scattering, which are the subject of nonlinear optics. CARS and SRS are the most common techniques and are considered promising tools for studying molecular distributions in cells and tissues, as well as for visualizing biological structures [ 50 , 51 ]. CARS is a third-order nonlinear optical process in which photons of pump frequency ω p , the Stokes frequency ω S , and probe frequency ω pr interact in such a way that a signal is generated in the anti-Stokes field at a frequency of ω AS = (ω p − ω S ) + ω pr when the frequency difference ω p − ω S matches the Raman-active molecular vibration Ω R .…”