Experimental set up of a scanning holographic microscope. Sketch of the experimental setup. M's are mirrors, BS's are beam splitters, EO is an electro-optic phase modulator. Lens L1 (achromat doublet 16 cm focal length) produces the desired Fresnel pattern in the focal plane of L2 (achromat doublet 16 cm focal length). L2 and the objective form a 4-f system projecting a reduced image of the Fresnel pattern onto the specimen. L3 (achromat doublet 12 cm focal length) projects the images of the pupils on the pinhole detector. (Not shown are the beam expanders used to illuminate the pupils).