OPTICAL ELEMENT

摘要

PROBLEM TO BE SOLVED: To obtain an optical element with high diffracting efficiency which is small in the number of manufacturing steps, relatively easy to manufacture, and can be integrated. SOLUTION: This optical element has a binary structure on the top surface of a substrate 6. The wave front of incident light is varied by varying the distribution state of the binary structure and thus varying the effective refractive index with the position in the top surface. The binary structure is a microstructure wherein the size of the surface of one set of binary structures is smaller than the wavelength of the incident light.