Single bottle beam generated by a gradient axicon

A new model of double-axicon was proposed for the first time. Based on the traditional axicon，a gradient on the vertex of an axicon was designed. When a plane wave illuminates the gradient axicon，two Bessel beams are formed and a Bottle beam generated between the Bessel beams. Bottle beams could be used as optical pipes，optical tweezers，optical spanners, and so on.Because the dark focus is surrounded in all directions by regions of higher intensity，and it shows important application perspective in life science and nanotechnology. The formation mechanism of the single Bottle beam was analyzed by geometrical optics. The transverse and longitudinal intensity distribution were also calculated and simulated using diffraction and interference theory，respectively. The result shows its significance in providing a guidance for the design and application of the gradient axicon.