Resolution and contrast enhancement in coherent anti-Stokes Raman-scattering microscopy.

We implement switching laser mode coherent anti-Stokes Raman-scattering (SLAM-CARS) microscopy to enhance the spatial resolution and contrast in label-free vibrational microscopy. The method, based on the intensity difference between two images obtained with Gaussian and doughnut-shaped modes, does not depend on the specimen and relies on minimal modifications of the typical CARS setup. We demonstrate subdiffraction resolution imaging of myelin sheaths in a mouse brainstem. A lateral resolution of 0.36λ(p) is achieved.