Manning - This design represents a third innovation relative to Brierley. Only a single side of the disk is used. This improves the mounting situation while allowing the back side of the disk to be used to compensate for the bending moment generated by the tilted front surface. Rather than using the reverse side of the disk to produce a complementary reflection, a cube corner reflector is used to invert the image of the disk so that a complementary reflection can be made from the same surface of the disk. As in a standard Michelson design, the infrared radiation emitted by the source is collimated and split. The beam reflected from the beamsplitter propagates to a fixed flat mirror, while the transmitted beam impinges on the rotating disk, then reflects to the cube corner reflector to be returned to the disk. A second reflection at the disk is complementary to the first, resulting in a beam of constant propagation angle which can be returned by the final flat stationary mirror exactly on itself and back to the beamsplitter. This is a tilt-compensated tilt interferometer. US patent 5,898,495 covering this design issued on April 27, 1999. The patent images may also be viewed.