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

A new type of accelerating beams that self-bend multiple times is exploited for image signal transmission, which is found to be more resilient to obstructions in the transmission link. Accelerating beams are a type of light beams that self-bend as they travel in free space without the help of any optical tool. Such beams are not only fascinating as they seemingly violate the axiom of light propagation in straight lines, they can also be useful for energy, substance or information delivery using light, in order to evade obstacles in the light paths for instance. However, existing demonstrated applications are limited to employing accelerating beams with convex trajectories such as parabola, which will result in vulnerable transmission under obstructions especially in information delivery.

Now, Mr. Wei Lin (Master student) and Mr. Yuanhui Wen (PhD student), under the supervision of Associate Prof. Yujie Chen and Prof. Siyuan Yu as well as other colleagues from the School of Electronics and Information Technology at Sun Yat-sen University, propose and demonstrate a new type of bendable image transmission based on accelerating beams with nonconvex trajectories (taking the helical trajectory as a typical example in our study). The image signal is encoded in the Fourier space of the beam and then transmitted with the beam moving along the designed curved path. It is found that because of the special mapping relationship between the Fourier space and real space possessed by the nonconvex accelerating beams, the image encoded in these beam is not as affected by obstructions as normal convex accelerating beams like Airy beams. Such discovery might be directly beneficial to future imaging and communication areas such as astronomical signal transmission, microscopic image transmission, etc., and moreover, inspire researchers to utilize the peculiar nonconvex light paths in a variety of accelerating beam-based applications beyond the conventional convex ones.

This work has been published in Physical Review Applied [12, 044058 (2019)], entitled “Resilient Free-Space Image Transmission with Helical Beams”. Mr. W. Lin and Mr. Y. Wen contributed equally to this work, and Associate Prof. Y. Chen is the corresponding author. This work was supported by National Natural Science Foundation of China (NSFC) (11774437, U1701661, 61490715), Science and Technology Program of Guangzhou (201804010302), Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01X121), and Science and Technology Planning Project of Guangdong Province (2018B010114002). Associate Prof. Chen and Prof. Yu are also with State Key Laboratory of Optoelectronic Materials and Technologies.

Link to the paper: https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.12.044058