An apparatus for transmitting or reflecting incident light. The apparatus includes a pair of diffraction grid substrates; a substantially grid-shaped diffraction grid formed of metal, wherein the diffraction grid is disposed between the substrates; and a pair of adhesive layers, each adhesive layer coupled to each substrate. The apparatus also includes a pair of block members, wherein each block member is coupled to each adhesive layer. The block member is configured with a plurality of substantially equally-shaped flat plate members alternately layered with adhesive layers for optically coupling the block member with substantially reduced optical distortion than when configured with a single transparent component. The block member includes a surface to output the light transmitted or reflected from the diffraction grid and passing through the flat plate members.