FRIDA IFU is conformed mainly by 2 mirror blocks with 30 spherical mirrors each. The image slicing is performed by a block of 30 cylindrical mirrors each of 400 μm width. It also has a Schwarzschild relay based on two off axis spherical mirrors that adapts the GTCAO corrected PSF to the slicer mirrors dimensions. To readapt the sliced PSF to the spectrograph input numerical aperture the IFU has an afocal system of two parabolic off axis mirrors. The AO PSF is bigger than the slice mirror dimensions and this produces diffraction effects. These diffraction effects combined with the intrinsic IFU and spectrograph aberrations produce the final instrumental PSF of the IFS mode.
In order to evaluate the instrumental PSF quality of the FRIDA IFS, modeling simulations were performed by the ZEMAX Physical Optics Propagation (POP) module. In this work the simulations are described and the PSF quality and uniformity on a reconstructed IFS image is evaluated. It is shown the PSF quality of the IFS mode including the instrument manufacturing tolerances fulfills the specifications.