Optical Trapping by Aperiodic Kinoform Lenses Based on the Baum–Sweet Sequence

This work presents a new family of aperiodic diffractive lenses based on the Baum–Sweet sequence. To the best of our knowledge, this is the first report of a diffractive lens derived from this sequence. The study of their focusing properties reveals two focal points with similar intensities along the optical axis. Both the main focal distances and the axial irradiance distribution are correlated with the aperiodic Baum–Sweet sequence. An approximate 60% increase in diffraction efficiency is observed when employing kinoform profiles instead of binary phase lenses. The integration of the Baum–Sweet-based kinoform lens into an optical tweezers system demonstrates its ability to simultaneously trap multiple particles at two distinct focal planes, highlighting its potential for applications in more advanced optical devices.