Source: School of Electronics and Information Technology
Written by: School of Electronics and Information Technology
Edited by: Wang Dongmei

Accelerating beams, as first proposed by Sir Michael Berry in the form of the Airy packets, are light beams capable of self-bending in free space. Such beams are not only fascinating as they seemingly violate the axiom of light propagation in straight lines, they can also be applied to either energy or information delivery using light, in fields ranging from optical interconnects, micro-manipulation, to laser plasma filamentation and plasmonics, where one may wish to evade obstacles in light paths, or for such deliveries to follow certain paths. However, existing theoretical framework limits demonstrated accelerating beams mostly to convex trajectories, with only a few limited and specific non-convex exceptions. The main technical approach based on bulk optics (such as spatial light modulators) is also not conducive to many applications.

Recently, researchers from State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, Sun Yat-sen University, led by Dr. Yujie Chen and Prof. Siyuan Yu, made important progress in winding light beams, solving these two main issues by developing a superposition caustic method and by means of an integrated optics approach. Firstly, they have developed a superposition caustic ray method capable of constructing accelerating beams along a wide variety of non-convex trajectories, which breaks the limitation of existing theoretical approaches. Secondly, they experimentally implemented this method by means of integrated micro-optics, demonstrating a robust and compact technical approach for winding light beams along arbitrarily elliptical helical trajectories. With these, their work may open up a new route of manipulating light beams for fundamental research and practical applications, paving the way for 'designed' beams trajectories and their implementation using further photonic integration technologies.

This work has been published in Physical Review A on 15 July 2016 [1], one of which figures has also been selected as part of the Journal’s "Kaleidoscope" [2]. Soon, a dedicated report [3] appeared in a popular scientific website, Physics Buzz, brings this work to the public. Very recently, Nature Photonics, one of the top-tier journals in photonics research community, has also published a Research Highlight to introduce this work in its current issue [4].

This work is supported by the National Basic Research Program of China (973 Program) (2014CB340000 and 2012CB315702), the National Natural Science Foundation of China (61323001, 61490715, 51403244, and 11304401), the Natural Science Foundation of Guangdong Province (2014A030313104), and State Key Laboratory of Optoelectronic Materials and Technologies.

[1] http://dx.doi.org/10.1103/PhysRevA.94.013829
[2] http://journals.aps.org/pra/kaleidoscope/July2016
[3] http://physicsbuzz.physicscentral.com/2016/07/winding-light-takes-new-paths.html
[4] http://www.nature.com/nphoton/journal/v10/n10/full/nphoton.2016.194.html