Understanding SSI – Subaperture Stitching

Introduction to SSI Subaperture Stitching Interferometry

In the evolving landscape of optical systems manufacturing, test results with high measurement accuracy are critical—especially for large aperture and aspherical surface components used in technologies such as astronomical telescopes and EUV lithography. Conventional interferometers struggle to capture precise full aperture measurements due to limitations in range and aberration correction. This is where Subaperture Stitching Interferometry (SSI) revolutionizes the field, offering a “block measurement-global reconstruction” method that ensures λ/10 precision (λ = 633 nm). SSI has become a go-to method for tests of large and complex optical components that feature rotational symmetry or freeform geometries. Learn More