Edge enhancement for in-phase focal modulation microscope

In-phase focal modulation microscopy (IPFMM) with single photon excited fluorescence is presented. Optical transfer functions and images of thin and thick fluorescent edges in IPFMM are investigated. The results show that, compared with confocal microscopy, using IPFMM can result in a sharper image of the edge, and the edge gradient can be increased up to 75.4% and 58.9% for a thick edge and a thin edge, respectively. Signal level is also discussed, and the results show that, to obtain high transverse resolution with IPFMM, the normalized detector pinhole radius should not exceed 2.8.