Measurement of nanomovements of an object from the optical phase image

We examine a method for measuring small movements of an object, based on calculation of the displacement of the image obtained using an optical interferometer. We estimate the effect of phase noise in reconstruction of the coherent structure of the field on the accuracy in measuring the movements. We have made practical estimates of the displacements of the real object from phase image data. We compare the estimates with the results of direct measurements of the displacements. We show that it is possible to detect movements of less than 10 nm using a commercial microscope.