Plano-Concave Axicon (Conical lens)

Plano-concave axicons have a plano surface in combination with a concave conical surface. Concave axicon produces a ring shaped image along the axis from a point light source (e.g. Gaussian laser beam). Due to specifics in fabrication process, a hole in the center of concave surface is needed. Diameter of the hole is typically >1 mm. Different coatings can be applied on the polished surfaces of axicons. When coated with HR coating, concave conical surface can be used as a conical mirror in some specific applications.