Convex fresnel lens with large grooves

The concentration capability of linear Fresnel lenses is limited mainly by coma and chromatic aberrations and by the width of the individual grooves of the lenses. We consider new designs for these lenses in which the concentration is almost independent of the groove's size, and which are free of coma at the edge of the acceptance field. Specifically, a concentration factor as high as 34 is achieved for monochromatic radiation coming from an acceptance angle of ± 1°.