A process for fabricating a reflective optical system is disclosed that includes providing first and second mandrels that form a mandrel assembly, and positioning the mandrel assembly in an electroforming bath. The process also includes performing an electroforming operation for a predetermined period, thereby forming an optical system on the mandrel assembly. The process further involves separating the mandrel assembly from the optical system. The resulting optical system is reflective and has at least first and second elongate hollow sections each having an axis corresponding to the axis of elongation of a respective mandrel. The reflective optical system may be used as an afocal relay and used in lithography applications.