REFRACTIVE AFOCAL OPTICAL SYSTEM FOR CORRECTION OF CHROMATIC ABERRATION OF DIFFRACTIVE IMAGING ELEMENTS

A refractive afocal optical system for correction of the chromatic aberration of diffractive imaging elements, more particularly the refractive afocal optical system (1) with angular magnification “ med for medium wavelength » med , for correction of the chromatic aberration of the diffractive imaging element (2), particularly for correction of the dispersion effects of the diffractive imaging element (2) of focal length f' diff,med and in combination with the diffractive optical element (2) for realization of an achromatic or apochromatic imaging system in the spectral band from the shortest wavelength » short to the longest wavelength » long , which includes m optical members (10, 20), wherein each of the optical members (10, 20) consists of a pair of refractive optical elements of focal lengths f' I,med , f' II,med , made from refractive optical materials, whose generalized Abbe numbers v I and v II are bound by the equation 1 v I ˆ’ 1 v II = ˆ’ » short ˆ’ » long » med f €² I , med mf €² diff , med , wherein the relative dispersion of all refractive optical materials used ranges from 0.49 to 0.51, and the focal length of the other member of the pair f' II,med is selected that the optical member is afocal for the medium wavelength » med . List of Reference Marks 1 optical system 2 diffractive imaging element 10 member I 11 lens I 12 lens II 20 member II 21 lens III 22 lens IV 101 surface I 102 surface II 103 surface III 104 surface IV 201 surface V 202 surface VI 203 surface VII 204 surface VIII