Compact, Wide-Angle Catadioptric Telescope Design for MWIR Imaging

Abstract

In this work, the optical design of a compact diffraction-limited F/3.0 MWIR (3-5 µm) catadioptric telescope which consists of an aspheric primary mirror, a spherical secondary mirror, a ZnSe-ZnSe-Ge triplet lens and an air-spaced Si-Ge-Si corrector triplet lens placed before the focus is given. The calculated effective focal length, full field of view (FFOV) and angular magnification values for the designed telescope are 600 mm, 2.6° and -9.2, respectively. Zemax® calculations for the telescope MTF (modulation transfer function), PSF (point spread function), RMS (root-mean-square) wavefront error (WFE), optical path difference (OPD), Seidel aberrations, encircled energy, distortion and field curvature are discussed. The telescope performance analysis indicates that the telescope can achieve diffraction-limited image quality performance within the 2.6° full field-of-view. Additionally, the designed telescope can resolve at 50% contrast spatial frequency equal to 18.5 cycles/mm (at the on-axis FOV). Finally, a detailed tolerance analysis for the telescope design employing Monte Carlo and sensitivity analysis simulation features in Zemax® is provided.