Super-resolution confocal microscopy using optical nonlinearity

The use of nonlinear optical effect can inherently boost the resolving power of laser scanning microscopy. We have proposed the use of saturated excitation in order to induce the higher order optical nonlinearities and extracted the nonlinear fluorescence response for improving the spatial resolution of confocal microscopy beyond the classical limit. We have demonstrated the technique can be used for high-resolution imaging of 3D samples. The technique can also be combined to nonlinear optical imaging techniques, such as two-photon excitation microscopy and CARS microscopy.