Optical element and optical pickup apparatus

摘要

The present invention provides an optical element including: a substrate; and an antireflection film formed on a surface of the substrate. The antireflection film includes a plurality of lower refractive index layers, and a plurality of higher refractive index layers which are layered alternately. Each of at least two of the plurality of lower refractive index layers comprises a same main component each other and comprises a side component with a different content ratio independently.