identified positions 1 2 and 3 correspond to particular rotational positions of the mirror 610 with respect to minor clusters 1 2 and 3 each of the mirror clusters imparts a different angle of rotation to the beams 614 and matching angle of rotation in the polarization associated with the beams the ipr 600 is operated as follows when the minor 610 is rotated into position 1 the beams 614 are reflected off of the mirror 610 toward mirror cluster 1 604 as represented by directional arrow 616 mirror cluster 1 604 rotates the beams and associated beam polarizations through a first rotational angle and reflects the beams back to the minor 610 as represented by directional arrow 617 when the minor 610 is rotated into position 2 the beams 614 are reflected off of the minor 610 toward minor cluster 2 605 as represented by directional arrow 618 minor cluster 2 605 rotates the beams through a second rotational angle and reflects the beams back to the minor 610 as represented by directional arrow 619 when the minor 610 is rotated into position 3 the beams 614 are reflected off of the minor 610 toward minor cluster 3 606 as represented by directional arrow 620 mirror cluster 3 606 rotates the beams through a third rotational angle and reflects the beams back to the minor 610 as represented by directional arrow 621 directional arrow 622 represents the rotated beams reflected off of the.