Spinning optical drills by dynamic high-order Bessel beam mixing

Structured light is one of the frontiers of modern photonics. It refers to the generation of customized optical fields based on wave-front shaping methods. It is a topic of intense research activity due to the wide range of applications in imaging, nonlinear optics, biophotonics (1). We propose, theoretically explore, and experimentally demonstrate "optical drill" beams presenting nonstationary intensity distributions that resemble the spinning mechanical drill. Optical drills appear as the spatiotemporal interference of two Bessel-vortex beams of different topological charges and different carrier frequencies. By mixing a pair of high-order Bessel beams, synthesized using a liquid crystal spatial light modulator, optical drills of tuned helicities were experimentally observed, and the simplest cases of light matter interaction (fluorescence) with such beams were demonstrated. The rotation in time was achieved by changing the offset of the hologram on the spatial light modulator. Optical drill beams could open new and revolutionary perspectives in dynamical material processing by light or in cell and particle manipulation in biomedical applications.