  The Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy
(SCALES) is an instrument being designed to perform direct imaging of
exoplanets in the mid-infrared (2-5 {\mu}m) with the Adaptive Optics System of
W.M. Keck Observatory. To eliminate unwanted thermal infrared radiation, SCALES
utilizes both a cold stop for excluding background radiation and a vector
vortex coronagraph with Lyot stops for starlight suppression. Optimal geometric
masks have been designed. We simulate the propagation of light through the Lyot
plane and analyze the on-axis images of stars in the K, L, and M band for the
performance of the Lyot stops. Additionally, finalized cold stop and Lyot stop
designs are presented along with evaluations on the effects of manufacturing
tolerances and tilt in pupil planes caused by off-axis parabolic mirror relays.
