Multi-contrast focal modulation microscopy for in vivo imaging of thick biological tissues.

In vivo high resolution imaging of biological tissues is desirable for a wide range of biomedical applications. Recently focal modulation microscopy (FMM) has been developed and an imaging depth comparable to multi-photon microscopy (MPM) and optical coherence microscopy (OCM) has been achieved. Here we report the first focal modulation microscope that is capable of performing real-time fluorescence and scattering imaging simultaneously on thick biological tissues. A novel spatiotemporal phase modulator (STPM) has been designed and integrated into such a microscope to achieve high performances in terms of imaging speed, contrast, effective spatial resolution, signal to noise ratio, and compatibility with multiple excitation wavelengths.