We are in charge of the manufacturing and delivery of all the super-polished mirrors of the NASA/WFIRST Coronagraphic Instrument, dedicated to exoplanets imaging and characterisation from space. The manufacturing method has been developed and optimised by PhD student Mélanie ROULET, who combined the potential of additive manufacturing with the stress-polishing technique, only technique capable to provide extremely smooth surfaces for freeform mirrors, with a roughness down to 2 Angströms.

The picture below illustrates the Power Spectral Density obtained after the stress polishing of the OAP #7 prototype, developed in the frame of the ERC ICARUS. This is compared to the 2*f^{-2.5} specification. The very low level of the PSD expresses the very low level of noise in the final image. The zone between [3;30] cycles per pupil corresponds to the zone where the exoplanets are located in the final image of the instrument. Getting a very low level of noise helps revealing the tiny exoplanets which luminosity is a million to a billion times lower than the parent star they are orbiting.