Interferometric characterization of a microaxicon with a single fringe pattern

The height and opening angle of a microaxicon are two important factors for the working distance and the field profile of the beam generated by the microaxicon. A simple approach for the characterization of a microaxicon is proposed and demonstrated with the single fringe pattern obtained from a modified Mach–Zehnder interferometer. The geometrical profile, height and opening angle are retrieved from the interference fringe pattern for a quartz microaxicon fabricated by direct laser writing and inductively coupled plasma etching, which are comparably consistent with that measured by an atomic force microscope.