Patent ID: 8749785

Claim:
A system for improving the operation of a focusing element as a function of wavelength for a multiplicity thereof comprising, in either order: a) a focusing element for focusing an electromagnetic beam, selected from the group consisting of: a lens; and a lens system comprising at least two elements; and b) a filtering element for naturally adjusting the effective cross-sectional area of a transmitted beam of electromagnetic radiation, as a function of wavelength; said element for focusing an electromagnetic beam not requiring any additional, beam shaping, elements; said focusing element and said filtering element being functionally associated; wherein the design criteria of said filtering element is that the effective cross-sectional area of the electromagnetic beam passed by said filtering element to said focusing element is naturally adjusted with respect to wavelength for each of a multiplicity thereof, such that the performance of the focusing element is rendered approximately optimum in view of an inherent tradeoff between diffraction and aberration effects as a function of electromagnetic beam cross-sectional area; wherein the terminology “naturally adjusted” means that a filter material optically responds to different wavelengths differently, so that an effective diameter, and therefore the cross-sectional area of a beam of electromagnetic radiation interacting with an associated focusing element, is different for different wavelengths.