Electroformed buried gratings for high-power shared aperture systems

摘要

A two-metal grating is produced by vacuum depositing a first dielectric coating upon a separation layer formed upon a mandrel; then depositing a first optically opaque metallic layer, etching the layer to form stripes; then vacuum depositing a second optically opaque film; then electroforming a backing structure and separating the dielectric coating from the separation layer on the mandrel to form a free-standing grating structure having a smooth surface. This structure can then be affixed to a metallic mirror. A buried phase grating can also be fabricated by additionally depositing a second dielectric layer and a third metallic layer.