Design of achromatized hybrid diffractive lens systems

The design of two broadband hybrid diffrve-refrve optical systems a landscape type lens and a Schmidt telescope was investigated. The systems were achromatized using the large negative dispersion characteristic of kinoforms. In the scalar wave regime these strucwres can approach 100 efficiency for one object point and wavelength but efficiency inevitably decreases when these parameters change. We evaluated polychromatic image quality taking diffraction efficiency into account by constructing properly weighted geometric point spread functions from several diffracted orders and calculating modulation transfer functions. The MTFs of the hybrid achmmats were improved at high spatial frequencies but reduced at low frequencies because inefficiency caused diffrtion into non-design ders. 2.