3-D Metrology and Correction of Aspheric Diffractive Optics

摘要

Historically, it has been challenging to measure diffractive optical surfaces and deterministically correct for symmetric and asymmetric errors inherent in the turning process. The diffractive zones (for IR applications) tend to fall between 3 microns and 25 microns in depth, depending on the refractive index of the material. Compared to common form error specifications of 0.150 microns to 0.633 microns, the large diffractive zones hide the true form error and make it challenging to measure, let alone correct for form error.