Danyong Zeng College of Optics & Photonics/Univ. of Central Florida (United States) William Pete Latham Air Force Research Lab. (United States) A. Kar College of Optics & Photonics/Univ. of Central Florida (United States)
An annular beam provides a new laser drilling mechanism, which we refer to as optical trepanning. A refractive axicon system has been designed to transform an input Gaussian laser beam into a collimated annular beam. The diffractive effects of the axicon system and a convex lens focusing the collimated annular beam have been studied using the Fresnel diffraction integral. The theoretical diffraction patterns are compared with the patterns measured with a laser-beam analyzer. The results show that the refractive axicon system can produce Gaussian-like annular beams with the capability of easily adjusting the size of the annular beam.