Fused Silica Axicon is a specialized type of lens which has a conical surface. Axicons, also commonly referred to as rotationally symmetric prisms, are lenses that feature one conical surface and one plano surface. They are commonly used to create a beam with a Bessel intensity profile or a conical, non-diverging beam. When converting a collimated beam into a ring, the plano side should face the collimated source.