Single-pinhole confocal differential phase contrast microscopy

A new technique for obtaining confocal differential phase contrast is outlined. It is shown that this method involving a single pinhole and a split detector is easier to align and calibrate than the standard method of two pinholes and two detectors. Experimental calibration curves, which show that this arrangement does perform differential phase contrast imaging and that it can be used to measure surface height variations of the order of λ/600 per micrometer, are presented. Confocal scanning-beam reflection and transmission differential phase contrast images are presented.