Optical Manipulation of Airborne Light-Absorbing Microparticles Using Structured Laser Beams

It is demonstrated how structured laser beams can be used to implement holographic optical tweezers for trapping and manipulating light-absorbing nano- and microparticles in the air. Two types of structured laser beams are investigated: polygon laser beams and superpositions of the Laguerre–Gauss modes with various carrier frequencies shifted relative to the propagation axis. The polygon laser beams generate arrays of optical bottle-beam traps, and the superpositions of the Laguerre–Gauss modes generate multiple light spots propagating along curved trajectories. The experiments have shown a possibility of optically trapping hundreds and thousands of airborne carbon nanoparticle agglomerations in a cuvette and passively guiding the trapped particles along a curved trajectory. The reported results can be used to develop laser manipulation systems for studying and transporting airborne nano- and microparticles.