Optical solutions for the multi-IFU instrument EAGLE for the European ELT

International audienceThis paper summarizes the different optical concepts developed for the EAGLE Phase A design. EAGLE will be an MOAO (Multi-object AO) IFU spectrometer operating between 0.8 and 2.5mum. The EAGLE consortium have developed different concepts for the challenging problem of acquiring more than twenty objects in the patrol field of view (FOV), correcting the wavefront along the line of sight to each of the objects and analyzing each object spatially and spectrally with an Integral Field Spectrograph. The target selection FOV will be >=20 square arcmin and the individual target FOV can be selected to be either 1.65×1.65arcsec or 1.65×3.3arcsec. They will be sampled spatially at 75mas and with spectral resolutions of 4000 and 10000. Optical designs for target acquisition systems, integral-field unit, and spectrographs have been developed. These will be compared and the expected performance will be described in terms of the number of targets, overall patrol field of view, individual field of view, throughput, spectral resolving power and image quality