Described herein is an apparatus for non-destructive testing that includes a cavity. The apparatus also includes an input element coupled with the cavity and configured to receive a laser beam and to direct the laser beam into the cavity. The apparatus additionally includes multiple output elements formed in the cavity and spaced apart along the cavity. Each output element of the multiple output elements is configured to direct a portion of the laser beam out of the cavity such that each portion of the laser beam directed out of a respective one of the multiple output elements has a substantially similar intensity.