Aberration compensation method for dual-focus beams considering the effect of spatial light modulators flyback regions

To meet the growing demand for high efficiency stealth dicing (SD), generating dual-focus in silicon to produce double dicing paths has been widely used. However, the challenges in dual-focus SD are the aberration compensation methods based on spatial light modulators (SLM). Until now, the effect of SLM flyback regions that causes focusing intensity reduction has not been considered. Here, an aberration compensation method that considers the effect of SLM flyback regions is proposed to enhance the focusing intensity. This method takes into account not only the total number of flyback regions but also their distribution corresponding to the laser intensity distribution. In addition, the total area of flyback regions is utilized to quantify the impact and determine the optimal compensating phase pattern. Through simulations and experiments, we investigate the generation and control of aberration compensated dual foci. The simulated results demonstrate excellent agreement with theoretical analysis. Moreover, a back crack propagation of 29.9 μm is achieved in the dual-focus SD experiment.