Interference microscopy of polymer fibres*

SUMMARY The paper describes the use of a double refracting interference microscope with variable amount and direction of wavefront shear for the study of synthetic polymer fibres. General theoretical aspects of the field of the differential interference contrast method, and practical problems related to the application of this method in fibre examination are discussed. Some improvements in the micro‐interferometric measurement of the birefringence and refractive indices of fibres are suggested. Advantages of the developed double refracting interference microscope with variable wavefront shear are discussed from the point of view of fibre microscopy, and illustrated by photomicrographs.