Slope-sensitive optical probe for freeform optics metrology

Freeform and conformal optics represent the next generation of optical systems where their utilization leads to more compact, lighter, and higher performance systems for solar collectors, consumer optics, and defense applications. Optical coordinate measuring machines present one option for accurate metrology of freeform components but have two limitations: metrology system errors and optical probe errors. In this work, we address the latter of the two by demonstrating a compact optical probe capable of fiber delivery and fiber detection to remove potential heats sources away from measured optic. A bench top demonstrator has yielded a displacement resolution below +/- 10 nm and has a noise floor of approximately +/- 18 mu rad for surface slope in two orthogonal directions. In this Proceedings, we discuss our probe concept, operating principle, and preliminary measurements with a bench top proof-of-concept system. The goal of this work is to ultimately integrate this probe into OptiPros UltraSurf, a 5-axis optical coordinate measuring machine for measuring freeform and conformal optics.