Kinematic mirror mount design for ultra-precision manufacturing, metrology, and system level integration for high performance visible spectrum imaging systems

Abstract High-performance freeform optical systems, designed for broad spectral imaging from the visible to the far infrared, place new demands on optical design, precision manufacturing, and precision metrology. To meet the tolerances on figure, roughness, and relative positioning in such systems requires the ability to perform metrology and manufacturing corrections on freeform optics in a continuous feedback loop. This feedback loop requires a common interface for machining and manufacturing platforms. This paper describes the design, analysis, and testing of such an interface suitable for use with single point diamond turning and deterministic micro-grinding. The interface utilizes a torsionally preloaded, robust, kinematic mount capable of supporting manufacturing process loads while maintaining the position repeatability in five degrees of freedom required for the measurement and correction of optical figure. Results from a prototype system demonstrate absolute in-plane position uncertainty less than 200 nm and 50 nm, respectively, and axial position uncertainty is 40 nm absolute and 10 nm relative. The absolute and relative angular positioning uncertainties less than 1 µrad and 0.25 µrad respectively. The results exceed the requirements for many optical systems. The mount is also suitable for use in opto-mechanical assembly, so that the same platform can be used for manufacturing, metrology, final assembly, testing, and service.