Three for the price of one: dynamically reconfigurable generation of Gaussian, flat-top, and vortex/donut beams

This work presents a novel, to the best of our knowledge, "three-by-one" beam shaping architecture capable of real-time switching among Gaussian, flat-top, and optical vortex/donut beam profiles. The system is based on a polarization-controlled Mach-Zehnder Interferometer (MZI), which enables an incoherent superposition between a Gaussian (LG₀₀) and a Laguerre-Gaussian vortex (LG_0ℓ) beam by rotating/tuning the incoming beam's linear polarization. By adjusting the relative weight of the two orthogonal polarization modes in the two arms of MZI, the recombined beam is transformed from a Gaussian peak to a vortex singularity filled with a Gaussian to achieve a high-quality flat-top beam and further to a pure vortex/donut beam. The experiments confirm that the three modes can be dynamically shaped without the need for realignment. This scheme can be used in situations where flexible, dynamic switching/adaptation between different spatial modes is required, such as in laser micro-processing/machining, microscopy, particle manipulation, and free space communication.