Exploring the efficiency of laser materials processing with tunable acoustic gradient (TAG) lens (Conference Presentation)

Abstract

A continuously growing interest to achieve highly efficient mass-production systems has catalyzed various developments in high-efficiency laser processing techniques. These techniques entail fast and cost-effective control of the laser beam position for high-throughput laser material processing with optimal efficiency. Tunable acoustic gradient (TAG) lens is a device that uses acoustic waves to radially excite a fluid-filled cylindrical cavity that allows ultra-fast variation in focal-length. By rapidly scanning the laser focal point along the optical axis, TAG lens enables rapid selection of the focal length on time scales shorter than 1μs and can provide an increased efficiency in the machining rate. In this presentation, we demonstrate how a TAG lens can be used to achieve high-throughput material processing. Previously we have shown that the TAG lens enables higher micromachining rates in various material systems. In a specific example of silicon, we achieve a nearly threefold increase in the machining rate while maintaining sharp side walls and a small spot size. Through a detailed analysis of taking the probability distribution of the optical scanning range into account we study how using TAG lens with various micromachining rates affect the material processing efficiency.