CHEOPS NIR IFS: exploring stars neighborhood spectroscopically

CHEOPS is a 2^nd generation VLT instrument for the direct detection of extrasolar planets. The project is currently in its Phase A. It consists of an high order adaptive optics system which provides the necessary Strehl ratio for the differential polarimetric imager (ZIMPOL) and an Integral Field Spectrograph (IFS). The IFS is a very low resolution spectrograph (R~15) which works in the near IR (0.95-1.7 mum), an ideal wavelength range for the ground based detection of planetary features. In our baseline design, the Integral Field Unit (IFU) is a microlens array of about 250x250 elements which will cover a field of view of about 3.5x3.5 arcsecs² in proximity of the target star. In this paper we describe the instrument, its preliminary optical design and the basic requirements about detectors. In a separate contribution to this conference, we present the very low resolution disperser.