Multi-channel beam axis parallelism calibration in multiple prism beam-splitter

Multiple prism beam splitter can enlarge the parallel beam width and arrange the intensity distribution, which is used in the experimental simulation of lightening optical emission with different intensity distribution and high parallelism multi-channel beam. In order to obtain multi-channel parallel beam, penta prism scanning method was applied to test the multi-channel beams- parallelism in four-prism beam splitter with four prisms equally separated in the mechanical foundation. After we acquired the intensity distribution diagrams related to multi-channel optical axis by CCD, the software of centroid deviation calculation was programmed to feedback the accurate site-deviation information for prism calibration, which had the advantages of simpleness and convenience. The calibrated four-prism beam splitter had the optical axis matching precision less than 3, 4 and 4.5 in x-direction, y-direction and zdirection respectively, and the ratio of four-beam parallel light-s intensity was about 8∶4∶2∶1. If the resolution of CCD is improved and the focal length of the objective is enlarged, the precision of optical axis matching will achieve the seconds order.