Axicon
![Diagram of Axicon and resulting Bessel Beam](/Images/godic/202412/22/Bessel_beam.svg5604.png")
An axicon is a specialized type of lens which has a conical surface. An axicon images a point source into a line along the optic axis, or transforms a laser beam into a ring. It can be used to turn a Gaussian beam into an approximation to a Bessel beam, with greatly reduced diffraction. Axicons were first proposed in 1954 by John McLeod.