Digital microscopy using phase-shifting digital holography with two reference waves

A lensless, coherent optical microscope is described that uses a version of phase-shifting digital holography (PSDH) in conjunction with a field backpropagation algorithm to form coherent images of transmission-type objects. The PSDH is implemented by use of only two reference waves, in contrast with the usual implementation that requires four quadrature phase-shifting reference waves. Therefore only two digital holograms need to be recorded, and the complexity of the microscopic system is reduced. Experimental results are presented that compare images generated from conventional Gabor digital holography, two-reference-wave PSDH, and conventional white-light microscopy.