Tight focusing of amplitude modulated HyGG type — II beam using high NA lens axicon

The focal field of high NA lens axicon with an amplitude modulated optical component is calculated by using vector diffraction theory. Numerical results show that for a radially polarized Hypergeometric-Gaussian type-II input field, the proposed system generates subwavelength focal spot size (0.386 λ) with a uniform depth of Focus (14.38 λ). We expect such a beam with small spot size and long depth of focus can be widely used in application such as data storage, biomedical imaging, laser drilling, and machining.