Abruptly autofocusing beams from phase perturbations having forced symmetry

MARTÍNEZ-MATOS, ÓSCAR; AMAYA, DAFNE; VAVELIUK, PABLO

OPTICS LETTERS

OPTICAL SOC AMER

Año: 2019 vol. 44 p. 3733 - 3736

0146-9592

A controllable manipulation of the energy distribution ofcaustic beams possessing rectangular symmetry is presented.The beams are designed from the spectral phase by adding alinear and/or quadratic perturbation having forced symmetry. This approach breaks the overall caustic structure intobranches, allowing a fully controllable displacement of eachbranch. The caustic breaking leads to peculiar propagationconfigurations for rectangular beams. Among them, we highlight the abruptly autofocusing beam, which until now wasexclusively associated to caustic beams with circular symmetry. Thereby, the abruptly autofocusing effect can beyielded for one-dimensional light sheets, contrary to whathappens for circularly symmetric beams. The theoretical predictions are supported by experiments. Besides, the focuswidth of such rectangular beams can be reduced beyondthe standard diffraction limit