Abstract: Optical media is imaged by a combination of components for splitting a coherent beam into two co-propagating optical beams; converging the optical beams to produce a pattern of interference fringes having a pitch; varying the pitch and/or amplitude of the interference pattern fringes; axially rotating the fringes around the media; and axially rotating the co-propagating optical beams so as to maintain rotary synchronism with the axially rotating fringes as the permanent fringes are formed in the media whereby the longitudinal index of refraction is modulated along the media preferably with circular symmetry. The media is positioned as a work piece along a workpiece axis, with some of the system components translated along and/or rotated about the workpiece axis. Independently variable design parameters can, according to the preferred control system, be specified in advance with a high degree of flexibility.