Device for focusing light onto a photosensitive object, preferably having laminar region, e.g. for microscopy, lithography, optical or magneto-optical data storage such as CD and DVD

摘要

Size of focal spot reduced by reducing wavelength through use of new laser-light sources or illuminating the object through a small diaphragm whose width is less than the illumination wavelength, etc. The electric field of the light in the region of the focal point now has a longitudinal component directed parallel to the optical axis of the focusing element. In systems for focusing light on to photosensitive regions of an object, where the light source is preferably a laser with at least one optical focusing element and where the photosensitive zone of the object is arranged at the focal point of the focusing element, there is an advantage of reducing the size of the focal spot relative to that of conventional illumination systems based on diffraction limits e.g. by reducing the wavelength through use of new laser-light sources or illuminating the object through a small diaphragm whose width is less than the illumination wavelength, etc. The electric field of the light in the region of the focal point now has a longitudinal component directed parallel to the optical axis of the focusing element.