Advanced laser beam shaping using spatial light modulators for material surface processing

Abstract

Beam shaping is the process of redistributing the irradiance and phase of a beam of optical radiation. The beam shape is defined by the irradiance distribution. In recent years, laser beam shaping has been employed in many fields of scientific, engineering and industrial R&D for many applications, such as material processing, medical applications, lithography, optical data storage and laboratory research. In this thesis, a novel beam shaping technique is presented. Different from geometrical optics and diffractive methods, an imaging-based beam shaping system was built and tested. A laser beam was shaped using geometric masks applied on a spatial light modulator (SLM) at objective plane of a lens system and reconstructed at imaging plane. Geometric masks generated based on real beam profile can modulate both the outline profile and intensity distribution of the input laser. Laser parallel processing technique was also employed in this research to increase the beam shaping efficiency. The results obtained in this thesis demonstrate high accuracy and flexibility of this beam shaping technique, showing many potential applications.