A phase jump phenomenon in interferometry

A phase jump phenomenon in interferometers is reported. When the intensity of one arm of an interferometer changes from greater to less (or less to gr eater) than that of another, a phase jump of 180 degrees will take place if the phase difference between two beams is fixed as pi. We name this phenom enon "phase jump.'' Both theoretical analysis and experimental verification are conducted and the results are presented here. The slope of the phase j ump is infinite and highly stable. Therefore, this phase jump phenomenon ca n be used as optical comparators, reference mark, position indexes, pulse g enerators, edge detection, etc. (C) 1998 American Institute of Physics. [S0 003-6951(98)02849-6].