Microscopic coherent Raman imaging using low-cost continuous wave lasers

Significant effort is devoted to improving the instrumentation for stimulated Raman scattering (SRS) microscopy, which plays an important role in non-invasive biomedical optical imaging by providing a chemically specific contrast without relying on fluorescent markers. In this work we employ low-cost continuous wave lasers to achieve highly sensitive SRS imaging suitable for future application in biology, medicine and materials science. We perform microscopic imaging of dimethyl sulfoxide using two independent, commonly used lasers: a diode pumped, intracavity doubled 532 nm laser and a He-Ne laser operating at 632.8 nm. We further demonstrate that SRS imaging using cw laser sources (cwSRS) is advantageous over pulsed laser based SRS, as it eliminates the possibility of sample damage due to exposure to high-intensity light radiation, while substantially reducing the cost and complexity of the setup and keeping a sub-micron spatial resolution.