Abstract

When optical wave propagates through an inhomogeneous medium the finite number of points occurrence is possible, where irradiance intensity equals to zero as consequence of partial waves interference.² The phase of the wave cannot be defined in these points and in their vicinity the phase surface can be described either as a multilist, three-dimensional surface or as a broken two-dimensional surface. In the last case the branch cuts connect the pairs of the screw dislocations with opposite sign.⁴

© 1994 IEEE