Формирование конической фокальной области при острой фокусировке

We investigate formation of conic focal area on the basis of apodization of high-numerical-aperture objective by diffractive fracxicon, which special case is linear axicon. Change of fracxicon’s parameter allows to vary elongation of conic distribution that provides formation of a subwavelength light spot in a sharp part of a cone. Similar to action of the narrow ring aperture reduction of the focal spot size is reached due to loss of energy in the center of focus. However the generated light cone allows to choose the best for the user a parity of power and geometrical characteristics of a focal spot by displacement from focus. At circular polarization efficiency of fracxicon both on compactness of a focal spot and under power characteristics is shown.