Improving micromachining process using a new mode converter system

In this paper, we investigate the intensity and phase structure of transversal laser modes and their effects on laser micromachining before and after using mode converters. Generally, transversal laser modes can be described by a real or complex product of a Hermite or Laguerre polynomial and a Gaussian function in 2D or 3D respectively. It is possible to transform HG modes into LG modes and vice versa. Furthermore, a multimode beam can be converted into other useful beam. Using cylindrical and spherical lenses with particular characteristics, we have developed a mode converter system to transform a multimode light used in micromachining into an ultra-narrow annulus beam that is independent of the number of modes and their orders in input beam. Furthermore, the experimental results validation is examined closely by our theoretical mode! as well as computer simulation which show an excellent agreement.