Fabrication of microcone array for antireflection structured surface usingmetal dotted pattern

An antireflection surface with sub-wavelength structure has been successful ly fabricated on a fused silica substrate. The fabricated antireflection st ructured surface consists of a microcone array of fused silica with a perio d shorter than the wavelengths of visible light. The microcone array is mad e by a reactive ion etching method using fluorocarbon plasma. A microdisk a rray of chromium thin film, formed by an electron-beam lithography and lift -off process, is used as the etching mask. Since an electric field induced near the substrate was focused on the edges of the metal disks, these disks gradually shrank. Consequently, a conical shape was formed. The fabricated cone array has a period of 250 urn and a height of 750 nm. Measured reflec tivity of the antireflection structured surface is less than 0.5% in the wa velength range of 400-800 nm for normal incidence.