Design, realization and testing of the NANOMEFOS non-contact measurement machine for freeform optics

By applying freeform optics (figure 1) in high-end optical systems such as used in space, science and lithography applications, system performance can be improved while decreasing the system mass, size and number of required components (for instance [1]). The applicability of classical metrology methods is limited for freeform surfaces, which is currently holding back their widespread application. TNO, TU/e and NMi VSL therefore initiated the NANOMEFOS project in 2004 [2]. The development of this universal non-contact and fast measurement machine with 30 nm uncertainty (2σ) for freeform optics up to AE500 mm is now nearing completion.