A compact fiber laser based stimulated Raman photothermal microscope with ease of operation

Fiber lasers have transformed microscopy with their robustness and portability. Fiber laser-based stimulated Raman scattering (SRS) offers label-free chemical imaging but faces challenges like noise and high light collection requirements. To overcome these, we introduce stimulated Raman photothermal (SRP) microscopy with fiber lasers. SRP detects thermal effects induced by SRS, reducing sensitivity to laser noise and eliminating balance detection needs. Our setup allows light collection through a low NA air condenser, simplifying operation for non-experts. SRP demonstrates superior sensitivity, particularly in media with high thermos-optic coefficients, outperforming fiber laser-based SRS. We showcase SRP's efficacy in imaging biological samples, promising enhanced sensitivity, resolution, and user-friendliness. This innovation signifies a significant step forward in biological microscopy, offering potential for widespread adoption and groundbreaking discoveries in vibrational imaging.