Melles Griot Absolute™ transmission flats cost-effectively increase the absolute
accuracy of Zygo®-style fizeau surface- and wavefront-testing interferometers
to λ/50 (peak to valley), without the need to store, manipulate, or subtract
reference wavefronts during the testing process. When reference wavefront
subtraction is employed, the absolute accuracy is significantly greater than
λ/50 (peak to valley). Absolute fizeau transmission and reference flats are
produced using advanced subaperture stitching interferometry (SSI®) and
magnetorheological finishing (MRF®).