PERIODIC STRUCTURE AND MEASUREMENT METHOD EMPLOYING SAME

摘要

According to the present invention, a plate-shaped periodic structure includes at least two aperture portions extending through the periodic structure in a direction perpendicular to a main surface of the periodic structure and periodically arranged in at least one direction along the main surface. Each of the aperture portions has a shape that is not mirror-symmetric with respect to an imaginary plane that is a plane perpendicular to the main surface. Each of the aperture portions includes a constricted portion at which a gap distance of the aperture portion is partially small, the gap distance being a width in a direction parallel to a line of intersection of the main surface and the imaginary plane.