The imaging system of PEMI II is optimized for the CCD camera as well as the large format camera. In conventional systems, magnified images can be recorded only at the center of the field, which means the specimen or interferometer must be moved in order to collect data at locations away from the center. As an important consideration, note that fringes in overlapping sections will be discontinuous if the specimen or interferometer is moved, whereas they will remain continuous when only the camera is moved. Zoom lenses of outstanding quality provide magnification control for the CCD camera. Mirrors are optically flat, zero expansion Zerodur with high efficiency dielectric coatings.
Construction materials are black hard-anodized structural aluminum and stainless steel.
Fasteners, springs, etc., are stainless steel. The system is built for optimum performance and longevity, with freedom from corrosion and degradation. The optical connection between the laser and interferometer is comprised of two single-mode, polarization preserving optical fibers, one each for the U and V fields. The fibers are protected by a robust but very flexible stainless steel conduit. Outstanding workmanship and components assure very smooth operation of all adjustments.