Fiber-Enhanced Stimulated Raman Scattering and Sensitive Detection of Dilute Solutions

Stimulated Raman scattering (SRS) is known to gain coherent amplification of molecular vibrations that allow for rapid and label-free chemical imaging in the microscopy setting. However, the tightly focused laser spot has limited the detection sensitivity, partly due to the tiny interaction volume. Here, we report the use of metal-lined hollow-core fiber (MLHCF) to improve the sensitivity of SRS in sensing dilute solutions by extending the light-matter interaction volume through the fiber waveguide. With a focusing lens (100 mm FL) and 320 mu m diameter fiber, we demonstrated an optimum enhancement factor of similar to 20 at a fiber length of 8.3 cm. More importantly, the MLHCF exhibited a significantly suppressed cross-phase modulation (XPM) background, enabling the detection of similar to 0.7 mM DMSO in water. Furthermore, the relationship between fiber length and SRS signal could be well explained theoretically. The fiber-enhanced SRS (FE-SRS) method may be further optimized and bears potential in the sensitive detection of molecules in the solution and gas phases.

Automated summary

In this study, metal-lined hollow-core fiber (MLHCF) was used to improve the sensitivity of stimulated Raman scattering (SRS) in sensing dilute solutions. By extending the light-matter interaction volume, MLHCF showed significant enhancement and suppressed cross-phase modulation (XPM) background at a certain fiber length. The fiber-enhanced SRS (FE-SRS) method has potential in sensitive detection of molecules in solution and gas phases.