Optical Axis Perturbation Analysis for the Unit-Magnification Multipass System

Figure 3

Schematic diagram of BHWC. Two objective mirrors and lay on one side and a field mirror locates on the other side with an interval close to . All mirrors have identical radii of curvature . is the curvature center of each mirror. Two-row images are formed on the field mirror with the column spacing and row spacing , where is the distance of curvature center of and . is the center shift of the input beam which represents the center point on the mirror .