Antireflection film, method for producing antireflection film, optical element, and optical system

An antireflection film that is provided on a substrate and is formed by laminating an interlayer, a silver-containing metal layer containing silver, and a dielectric layer, in this order, on the substrate,

• wherein the interlayer is a multilayer film having two or more layers, in which a layer of high refractive index having a relatively high refractive index and a layer of low refractive index having a relatively low refractive index are alternately laminated,
• wherein the dielectric layer has a surface to be exposed to air and is a multilayer film having two or more layers including an oxide layer and a fluorocarbon layer, which is a self-assembled film that is formed by a silane coupling reaction to the oxide layer,
• wherein the dielectric layer includes a silicon oxide layer, and a layer having a refractive index lower than a refractive index of the silicon oxide layer, and
• wherein the layer having a refractive index lower than a refractive index of the silicon oxide layer is provided nearer to the silver-containing metal layer than the oxide layer.