Fig. 14.
Comparison of predicted image quality for three different designs of the same afocal telescope: (Δ) original, (o) off-the-plane, and ( + ) toroidal. The original has both mirrors spherical with beam confined to a single plane. Off-the-plane has both mirrors spherical with beam directed off the plane at 90° by the second mirror. Toroidal has the second mirror a toroid. Each plot shows the wavefront RMS error as a function of incident angle, I1, at the first mirror of the telescope. Left and right columns correspond to telescope #5 (1000:500) and #4 (300:1000), respectively, from the Indiana AO-OCT system (see legend of Fig. 5). Telescopes are optimized for (top row) pupil (finite) an (bottom row) retina (infinite) conjugate cases. Incident beam diameter was 6.67 mm. Wavelength was 809 nm, center of the AO-OCT system spectrum. Dashed lines represent diffraction-limited performance (RMS = λ/14).