The Investigation Pulsed Laser Beams Focusing Using a Refractive Microaxicon with the Variable Opening Angle

We performed calculations of focusing of pulsed laser linearly-polarized Gaussian beams using refractive microaxicons with aperture angles from 10° to 30° and demonstrated the change in the output field when the wavelength of the incident beam is varied at a given value of the opening angle of a microaxicon. The displacement of the maximum of the intensity distribution towards the apex of the axicon was observed with an increase in the opening angle. For a number of cases, a cyclic change in the shape of the output beam was observed, and a change in the states of the output beam from a focused beam to a halo (a divergence of the output beam) at a high angle apex was demonstrated.