Shaping caustics into propagation-invariant light

Alessandro Zannotti (1) , Cornélia Denz (1) , Miguel Alonso (2) , Mark Dennis (3)

1 WWU - Westfälische Wilhelms-Universität Münster = University of Münster
2 MOSAIC - MOSAIC
3 University of Bristol [Bristol]

Structured light has revolutionized optical particle manipulation, nano-scaled material processing , and high-resolution imaging. In particular, propagation-invariant light fields such as Bessel, Airy, or Mathieu beams show high robustness and have a self-healing nature. To generalize such beneficial features, these light fields can be understood in terms of caustics. However, only simple caustics have found applications in material processing, optical trapping , or cell microscopy. Thus, these technologies would greatly benefit from methods to engineer arbitrary intensity shapes well beyond the standard families of caustics. We introduce a general approach to arbitrarily shape propagation-invariant beams by smart beam design based on caustics. We develop two complementary methods, and demonstrate various propagation-invariant beams experimentally, ranging from simple geometric shapes to complex image configurations such as words. Our approach generalizes caustic light from the currently known small subset to a complete set of tailored propagation-invariant caustics with intensities concentrated around any desired curve.

Domaines: Physique [physics]; Optique [physics.optics]

Alessandro Zannotti, Cornélia Denz, Miguel Alonso, Mark Dennis. Shaping caustics into propagation-invariant light. Nature Communications, 2020, 11 (1), ⟨10.1038/s41467-020-17439-3⟩. ⟨hal-02902860⟩