The Eyeglass is a very large aperture (25–100-m) space telescope consisting of two distinct spacecraft, separated in space by several kilometers. A diffractive lens provides the telescope’s large aperture, and a separate, much smaller, space telescope serves as its mobile eyepiece. Use of a transmissive diffractive lens solves two basic problems associated with very large aperture space telescopes; it is inherently launchable (lightweight, packagable, and deployable) it and virtually eliminates the traditional, very tight surface shape tolerances faced by reflecting apertures. The potential drawback to use of a diffractive primary (very narrow spectral bandwidth) is eliminated by corrective optics in the telescope’s eyepiece; the Eyeglass can provide diffraction-limited imaging with either single-band (Δλ/λ ~ 0.1), multiband, or continuous spectral coverage.
© 1999 Optical Society of America
Roderick A. Hyde, "Eyeglass. 1. Very Large Aperture Diffractive Telescopes," Appl. Opt. 38, 4198-4212 (1999)