Acousto-optically controlled optical tweezers

Subject of study. The subject is Bragg diffraction of a laser beam by a multifrequency acoustic wave in a paratellurite crystal to form several beams deflected in specified directions. Aim of study. A method and apparatus are developed for simultaneously moving several transparent microparticles along arbitrary trajectories using acousto-optically focused laser beams. In particular, operating modes for acousto-optically controlled optical tweezers that permit simultaneous automated manipulation of multiple microscopic objects, varying the number of traps, the strength of the traps, and the trajectories of the microscopic objects, are developed and tested. Methods. Particle movement is implemented by controlling the position of the optical trap formed by a focused laser beam whose 2D deviation is performed by a multichannel acousto-optic deflector developed as part of this research. The particle rearrangement process is automatically controlled by specifying the individual particle trajectories on a screen. Main results. An experimental test bench based on an inverted biological microscope was developed. This test bench allows the positions of the particles and traps to be displayed on the screen in real time. Microscopic particles of nutritional yeast were used to experimentally demonstrate that it is possible to simultaneously control an ensemble of microscopic objects using a multichannel 2D nonmechanical deflector. Practical significance. The hardware and software tools developed herein can be used in biomedicine and materials science for automated, precise, and high-performance manipulation of multiple microscopic objects. (c) 2024 Optica Publishing Group