Optical Blaster: Launching Nanostructured Microrockets out of an Optical Trap by a Single Laser Beam.

Precise manipulation of microscopic objects is crucial for applications in biomedicine, robotics, and nanotechnology. However, achieving stable trapping, controlled release, and rapid propulsion with a single laser beam remains a significant challenge. Here, we elucidate the optical forces and torques exerted on chiral liquid crystal polymer microparticles when the laser wavelength is within their photonic bandgap and demonstrate the application in an optical blaster. Photons with polarization handedness opposite that of the chiral helical structure in the particle are transmitted and can be used to trap the particle, while photons with the same polarization handedness lead to a strong recoil effect. By leveraging this mechanism, we create an optical blaster that first loads the microparticles into the optical trap and subsequently launches them as microrockets by switching the circular polarization handedness of the light beam. The particles achieve propulsion speeds up to 234 μm s and finally levitate well above the laser focus after a balance between gravity and the optical force is reached. The optical blaster concept holds promise for diverse applications in ultrafast cargo transport, soft microrobots, microsurgery, and the advanced nanomanipulation of small objects.