LIGHT DIFFRACTION ELEMENT UNIT, MULTISTAGE LIGHT DIFFRACTION DEVICE, AND MANUFACTURING METHOD FOR MULTISTAGE LIGHT DIFFRACTION DEVICE

摘要

Provided is a light diffraction element unit such that it is possible to make adjustments in the in-plane direction and define the interval between light diffraction element units that are adjacent in the layering direction. A light diffraction element unit (11i) comprises: a substrate (11ai); a light diffraction element (11c1); and a three-dimensional alignment mark (alignment mark 11b1) that is provided in the vicinity of the light diffraction element (11c1) and that has a thickness greater than that of the light diffraction element (11c1).