Short coherence length produced by a spatial incoherent source applied for the Linnik-type interferometer

An axial resolution created by a spatial incoherent source is investigated theoretically and experimentally for the Linnik-type interferometer. The axial resolution in interference microscopy depends on both the temporal coherence length of the source and the objective numerical aperture (NA). Here the problem is treated in a more general situation by considering the spatial and temporal coherence of the illumination source which may be important for deep coherence imaging application. The results show that the axial resolution is degraded at the depth much less by using the optimal spectral bandwidth of the incoherent source and high-NA objectives.