The role of phase–polarization interactions in the laser processing of polarization-sensitive materials

Taking into account phase-polarization interactions is crucial for the formation of spatially structured laser beams. The effects that arise in this context can lead to the modulation of individual field components and the transformation of the overall light field. In this study, we investigate the impact of phase and polarization distributions with radial dependencies in polar coordinates on the longitudinal component of laser beams passing through a transmissive spatial light modulator (SLM) based on twisted nematic liquid crystals. Although the amplitude, phase, and polarization distribution of the transformed light field behind the SLM do not depend on the azimuthal angle, the structure of the longitudinal component of the field exhibits a spiral shape. By utilizing the shaped light fields and a projection lithography technique, we demonstrate the feasibility of fabricating spiral microaxicons in thin films of polarization-sensitive materials. We also show that the direction of the spiral twist and the period of the microaxicon can be controlled by manipulating the parameters of the masks displayed on the SLM. Furthermore, we demonstrate the potential for the parallel fabrication of arrays of such microelements. The results obtained show that precise laser processing of photosensitive materials requires taking into account possible phase-polarization interactions of the illuminating laser radiation.