Tunable creation of ultralong anti-diffracting beam in free space by multiple energy oscillations mechanism manipulated with optical pen.
Light beam propagating with infinite anti-diffracting distance requires infinite power to preserve its shape. However, finite power in free space is a physical barrier that makes the problem insurmountable in decades. Here, we report a new method to break through this barrier by employing multiple energy oscillations mechanism, permitting the creation of light beam with ultralong anti-diffracting distance in free space. The anti-diffracting distance is no longer restricted by finite power in free space, but the number of energy oscillation, which is composed of energy charge and discharge of airy beam. This unprecedented propagative behaviour is attributed to a revolutionized understanding of non-diffractive light beam that when airy beam finishes energy discharge, it cannot recharge again. A versatile optical pen is therefore developed to manipulate the number, amplitude, position and phase of energy oscillation in arbitrary numerical aperture of focusing lens so that energy recharge can be occurred in free space and multiple energy oscillations are realized. The light beam with tunable number of energy oscillations is eventually generated in free space and propagates in a wavy trajectory. This work will facilitate the study of non-diffractive light beams to a new level and their applications in optics, and open up new avenues to other research fields, such as electronics and acoustics.
Publisher URL: http://arxiv.org/abs/1710.11084