Spectrographs with holographic gratings on freeform surfaces: design approach and application for the LUVOIR mission

Eduard Muslimov (1) , Marc Ferrari (1) , Emmanuel Hugot (1) , Jean-Claude Bouret (1) , Coralie Neiner (2) , Simona Lombardo (1) , Gerard Lemaitre , Robert Grange (1)

1 LAM - Laboratoire d'Astrophysique de Marseille
2 GEPI - Galaxies, Etoiles, Physique, Instrumentation

In the present paper we demonstrate the approach to use a holographic grating on a freeform surface for advanced spectrographs design. On the example POLLUX spectropolarimeter medium-UV channel we chow that such a grating can operate as a cross-disperser and a camera mirror at the same time. It provides the image quality high enough to reach the spectral resolving power of 126 359-133 106 between 11.5 and 195 nm, which is higher than the requirement. Also we show a possibility to use a similar element working in transmission to build an unobscured double-Schmidt spectrograph. The spectral resolving power reaches 2750 for a long slit. It is also shown that the parameters of both the gratings are feasible with the current technologies.

Mots clés: freeform optics; holographic grating; spectral resolution; LUVOIR mission; optical design

Domaines: Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]

Eduard Muslimov, Marc Ferrari, Emmanuel Hugot, Jean-Claude Bouret, Coralie Neiner, et al. (Dir.). Spectrographs with holographic gratings on freeform surfaces: design approach and application for the LUVOIR mission. In press. ⟨hal-01796075⟩