Winding light beams along elliptical helical trajectories

TL;DR

This paper introduces a superposition caustic method to generate non-convex accelerating light beams along elliptical helical paths, demonstrated through experimental fabrication of micro-optical structures on quartz glass.

Contribution

A novel superposition caustic technique enabling the creation of non-convex, arbitrarily shaped accelerating light beams, extending beyond traditional convex trajectories.

Findings

Successfully generated sinusoidal and elliptical helical accelerating beams

Experimental implementation with integrated optics on quartz glass

Method applicable to a wide variety of non-convex trajectories

Abstract

Conventional caustic methods in real or Fourier space produced accelerating optical beams only with convex trajectories. We develop a superposition caustic method capable of winding light beams along non-convex trajectories. We ascertain this method by constructing a one-dimensional (1D) accelerating beam moving along a sinusoidal trajectory, and subsequently extending to two-dimensional (2D) accelerating beams along arbitrarily elliptical helical trajectories. We experimentally implement the method with a compact and robust integrated optics approach by fabricating micro-optical structures on quartz glass plates to perform the spatial phase and amplitude modulation to the incident light, generating beam trajectories highly consistent with prediction. The theoretical and implementation methods can in principle be extended to the construction of accelerating beams with a wide variety of non-convex trajectories, thereby opening up a new route of manipulating light beams for fundamental research and practical applications.