In-line balanced detection stimulated Raman scattering microscopy

We introduce a novel confguration for stimulated Raman scattering (SRS) microscopy, called In-line Balanced Detection (IBD), which employs a birefringent plate to generate a time-delayed polarizationmultiplexed collinear replica of the probe, acting as a reference. Probe and reference cross the sample at the same position, thus maintaining their balance during image acquisition. IBD can be implemented in any conventional SRS setup, by adding a few simple elements, bringing its sensitivity close to the shotnoise limit even with a noisy laser. We tested IBD with a fber-format laser system and observed signalto-noise ratio improvement by up to 30dB.