Silicon micro machined binary lenses for infrared optics

The refractive binary aplanatic lenses with dimensions of the wavelength scale have been fabricated and characterized by optical measurements. We fabricated lenses with f/D ratio close to one where f is the effective focal length and D is the lens diameter. Light intensity was measured on the focal surface of lenses using three independent methods and it has been demonstrated that IR light energy was concentrated within an area of diameter probably smaller than 20 /spl mu/m. Operation of such lens cannot be explained on the basis of ray optics or simulated using scalar diffraction theory which provided contradictory results.