OPTICAL ELEMENT, OPTICAL COMPOSITE ELEMENT, AND OPTICAL COMPOSITE ELEMENT HAVING ATTACHED PROTECTIVE FILM

This optical element has, on one surface thereof, a plurality of recessed sections arranged at a most frequent pitch equal to or less than the wavelength of light in the operating environment, the optical element having, when seen in plan view, a plurality of domains in which the plurality of recessed sections are aligned in a predetermined arrangement, and a plurality of protruding sections formed in a region sandwiched between the plurality of domains and/or in a region surrounded by the plurality of recessed sections inside the domains, the plurality of protruding sections accounting for a surface area ratio of 1%-15% as seen in plan view.