Axicon lens (conical lens)

Plano-concave axicons have a plano surface in combination with a concave conical surface. They are made of optically transparent or filter materials with two polished surfaces, grounded edges and chamfers. An axicon made up of conical and flat surface produces a ring shaped image along the axis from a point light source. Due to the fabrication process, a central hole is needed to produce a concave conical surface. Hole diameter is typically 1 mm.

Surface Figure L/4 @ 632.8 nm
Surface Quality, scratch & dig 40-20
Apex Angle Tolerance, arcmin +/-0.5
Clear Aperture, % 90
Design Wavelength, nm 633
Diameter Tolerance, mm +0.0, -0.15
Thickness Tolerance, mm +/-0.1